diff --git a/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator.swift b/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator.swift
index 6dfcebb0..b0b4e281 100644
--- a/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator.swift
+++ b/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/LMInstantiator.swift
@@ -229,14 +229,15 @@ extension vChewingLM {
 
     /// 插入臨時資料。
     /// - Parameters:
-    ///   - key: 索引鍵。
+    ///   - key: 索引鍵陣列。
     ///   - unigram: 要插入的單元圖。
     ///   - isFiltering: 是否有在過濾內容。
-    public func insertTemporaryData(key: String, unigram: Megrez.Unigram, isFiltering: Bool) {
+    public func insertTemporaryData(keyArray: [String], unigram: Megrez.Unigram, isFiltering: Bool) {
+      let keyChain = keyArray.joined(separator: "-")
       _ =
         isFiltering
-        ? lmFiltered.temporaryMap[key, default: []].append(unigram)
-        : lmUserPhrases.temporaryMap[key, default: []].append(unigram)
+        ? lmFiltered.temporaryMap[keyChain, default: []].append(unigram)
+        : lmUserPhrases.temporaryMap[keyChain, default: []].append(unigram)
     }
 
     /// 自當前記憶體取得指定使用者子語言模組內的原始資料體。
@@ -279,60 +280,62 @@ extension vChewingLM {
     }
 
     /// 根據給定的索引鍵來確認各個資料庫陣列內是否存在對應的資料。
-    /// - Parameter key: 索引鍵。
+    /// - Parameter key: 索引鍵陣列。
     /// - Returns: 是否在庫。
-    public func hasUnigramsFor(key: String) -> Bool {
-      key == " " || (!unigramsFor(key: key).isEmpty && !key.isEmpty)
+    public func hasUnigramsFor(keyArray: [String]) -> Bool {
+      let keyChain = keyArray.joined(separator: "-")
+      return keyChain == " " || (!unigramsFor(keyArray: keyArray).isEmpty && !keyChain.isEmpty)
     }
 
     /// 根據給定的索引鍵和資料值，確認是否有該具體的資料值在庫。
     /// - Parameters:
-    ///   - key: 索引鍵。
+    ///   - key: 索引鍵陣列。
     ///   - value: 資料值。
     /// - Returns: 是否在庫。
-    public func hasKeyValuePairFor(key: String, value: String) -> Bool {
-      unigramsFor(key: key).map(\.value).contains(value)
+    public func hasKeyValuePairFor(key: [String], value: String) -> Bool {
+      unigramsFor(keyArray: key).map(\.value).contains(value)
     }
 
     /// 給定讀音字串，讓 LMI 給出對應的經過處理的單元圖陣列。
     /// - Parameter key: 給定的讀音字串。
     /// - Returns: 對應的經過處理的單元圖陣列。
-    public func unigramsFor(key: String) -> [Megrez.Unigram] {
-      guard !key.isEmpty else { return [] }
+    public func unigramsFor(keyArray: [String]) -> [Megrez.Unigram] {
+      let keyChain = keyArray.joined(separator: "-")
+      guard !keyChain.isEmpty else { return [] }
       /// 給空格鍵指定輸出值。
-      if key == " " { return [.init(value: " ")] }
+      if keyChain == " " { return [.init(value: " ")] }
 
       /// 準備不同的語言模組容器，開始逐漸往容器陣列內塞入資料。
       var rawAllUnigrams: [Megrez.Unigram] = []
 
-      if isCassetteEnabled { rawAllUnigrams += Self.lmCassette.unigramsFor(key: key) }
+      if isCassetteEnabled { rawAllUnigrams += Self.lmCassette.unigramsFor(key: keyChain) }
 
       // 如果有檢測到使用者自訂逐字選字語料庫內的相關資料的話，在這裡先插入。
       if isSCPCEnabled {
-        rawAllUnigrams += lmPlainBopomofo.valuesFor(key: key).map { Megrez.Unigram(value: $0, score: 0) }
+        rawAllUnigrams += lmPlainBopomofo.valuesFor(key: keyChain).map { Megrez.Unigram(value: $0, score: 0) }
       }
 
       // 用 reversed 指令讓使用者語彙檔案內的詞條優先順序隨著行數增加而逐漸增高。
       // 這樣一來就可以在就地新增語彙時徹底複寫優先權。
       // 將兩句差分也是為了讓 rawUserUnigrams 的類型不受可能的影響。
-      rawAllUnigrams += lmUserPhrases.unigramsFor(key: key).reversed()
+      rawAllUnigrams += lmUserPhrases.unigramsFor(key: keyChain).reversed()
 
-      if !isCassetteEnabled || isCassetteEnabled && key.charComponents[0] == "_" {
+      if !isCassetteEnabled || isCassetteEnabled && keyChain.charComponents[0] == "_" {
         // LMMisc 與 LMCore 的 score 在 (-10.0, 0.0) 這個區間內。
-        rawAllUnigrams += lmMisc.unigramsFor(key: key)
-        rawAllUnigrams += lmCore.unigramsFor(key: key)
-        if isCNSEnabled { rawAllUnigrams += Self.lmCNS.unigramsFor(key: key) }
+        rawAllUnigrams += lmMisc.unigramsFor(key: keyChain)
+        rawAllUnigrams += lmCore.unigramsFor(key: keyChain)
+        if isCNSEnabled { rawAllUnigrams += Self.lmCNS.unigramsFor(key: keyChain) }
       }
 
       if isSymbolEnabled {
-        rawAllUnigrams += lmUserSymbols.unigramsFor(key: key)
+        rawAllUnigrams += lmUserSymbols.unigramsFor(key: keyChain)
         if !isCassetteEnabled {
-          rawAllUnigrams += Self.lmSymbols.unigramsFor(key: key)
+          rawAllUnigrams += Self.lmSymbols.unigramsFor(key: keyChain)
         }
       }
 
       // 新增與日期、時間、星期有關的單元圖資料
-      rawAllUnigrams.append(contentsOf: queryDateTimeUnigrams(with: key))
+      rawAllUnigrams.append(contentsOf: queryDateTimeUnigrams(with: keyChain))
 
       // 提前處理語彙置換
       if isPhraseReplacementEnabled {
@@ -344,7 +347,7 @@ extension vChewingLM {
       }
 
       // 讓單元圖陣列自我過濾。在此基礎之上，對於相同詞值的多個單元圖，僅保留權重最大者。
-      rawAllUnigrams.consolidate(filter: .init(lmFiltered.unigramsFor(key: key).map(\.value)))
+      rawAllUnigrams.consolidate(filter: .init(lmFiltered.unigramsFor(key: keyChain).map(\.value)))
       return rawAllUnigrams
     }
   }
diff --git a/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/SubLMs/lmUserOverride.swift b/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/SubLMs/lmUserOverride.swift
index 414f36b2..7fbe8416 100644
--- a/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/SubLMs/lmUserOverride.swift
+++ b/Packages/vChewing_LangModelAssembly/Sources/LangModelAssembly/SubLMs/lmUserOverride.swift
@@ -69,7 +69,7 @@ extension vChewingLM {
       var headIndex = 0
       guard let nodeIter = currentWalk.findNode(at: cursor, target: &headIndex) else { return .init() }
       let key = vChewingLM.LMUserOverride.formObservationKey(walkedNodes: currentWalk, headIndex: headIndex)
-      return getSuggestion(key: key, timestamp: timestamp, headReading: nodeIter.key)
+      return getSuggestion(key: key, timestamp: timestamp, headReading: nodeIter.joinedKey())
     }
   }
 }
@@ -329,15 +329,15 @@ extension vChewingLM.LMUserOverride {
     arrNodes = Array(arrNodes.reversed())
 
     let kvCurrent = arrNodes[0].currentPair
-    guard !kvCurrent.key.contains("_") else {
+    guard !kvCurrent.joinedKey().contains("_") else {
       return ""
     }
 
     // 字音數與字數不一致的內容會被拋棄。
-    if kvCurrent.key.split(separator: "-").count != kvCurrent.value.count { return "" }
+    if kvCurrent.keyArray.count != kvCurrent.value.count { return "" }
 
     // 前置單元只記錄讀音，在其後的單元則同時記錄讀音與字詞
-    let strCurrent = kvCurrent.key
+    let strCurrent = kvCurrent.joinedKey()
     var kvPrevious = Megrez.Compositor.KeyValuePaired()
     var kvAnterior = Megrez.Compositor.KeyValuePaired()
     var readingStack = ""
@@ -354,19 +354,19 @@ extension vChewingLM.LMUserOverride {
     }
 
     if arrNodes.count >= 2,
-      !kvPrevious.key.contains("_"),
-      kvPrevious.key.split(separator: "-").count == kvPrevious.value.count
+      !kvPrevious.joinedKey().contains("_"),
+      kvPrevious.joinedKey().split(separator: "-").count == kvPrevious.value.count
     {
       kvPrevious = arrNodes[1].currentPair
-      readingStack = kvPrevious.key + readingStack
+      readingStack = kvPrevious.joinedKey() + readingStack
     }
 
     if arrNodes.count >= 3,
-      !kvAnterior.key.contains("_"),
-      kvAnterior.key.split(separator: "-").count == kvAnterior.value.count
+      !kvAnterior.joinedKey().contains("_"),
+      kvAnterior.joinedKey().split(separator: "-").count == kvAnterior.value.count
     {
       kvAnterior = arrNodes[2].currentPair
-      readingStack = kvAnterior.key + readingStack
+      readingStack = kvAnterior.joinedKey() + readingStack
     }
 
     return result
diff --git a/Packages/vChewing_Shared/Sources/Shared/Protocols/CtlCandidateProtocol.swift b/Packages/vChewing_Shared/Sources/Shared/Protocols/CtlCandidateProtocol.swift
index 5ad0602b..d891a44e 100644
--- a/Packages/vChewing_Shared/Sources/Shared/Protocols/CtlCandidateProtocol.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/Protocols/CtlCandidateProtocol.swift
@@ -9,7 +9,7 @@
 import Cocoa
 
 public protocol CtlCandidateDelegate {
-  func candidatePairs(conv: Bool) -> [(String, String)]
+  func candidatePairs(conv: Bool) -> [([String], String)]
   func candidatePairSelected(at index: Int)
   func candidatePairRightClicked(at index: Int, action: CandidateContextMenuAction)
   func candidates(_ sender: Any!) -> [Any]!
diff --git a/Packages/vChewing_Shared/Sources/Shared/Protocols/IMEStateProtocol.swift b/Packages/vChewing_Shared/Sources/Shared/Protocols/IMEStateProtocol.swift
index 5825b639..f2f9a3f8 100644
--- a/Packages/vChewing_Shared/Sources/Shared/Protocols/IMEStateProtocol.swift
+++ b/Packages/vChewing_Shared/Sources/Shared/Protocols/IMEStateProtocol.swift
@@ -15,7 +15,7 @@ public protocol IMEStateProtocol {
   var isASCIIMode: Bool { get set }
   var isVerticalTyping: Bool { get set }
   var isVerticalCandidateWindow: Bool { get set }
-  var candidates: [(String, String)] { get set }
+  var candidates: [([String], String)] { get set }
   var hasComposition: Bool { get }
   var isCandidateContainer: Bool { get }
   var displayedText: String { get }
@@ -49,7 +49,7 @@ public protocol IMEStateDataProtocol {
   var isFilterable: Bool { get }
   var isVerticalTyping: Bool { get set }
   var isMarkedLengthValid: Bool { get }
-  var candidates: [(String, String)] { get set }
+  var candidates: [([String], String)] { get set }
   var displayedText: String { get set }
   var displayedTextConverted: String { get }
   var tooltipBackupForInputting: String { get set }
diff --git a/Source/Modules/IMEState.swift b/Source/Modules/IMEState.swift
index f9cbfa51..eb58664c 100644
--- a/Source/Modules/IMEState.swift
+++ b/Source/Modules/IMEState.swift
@@ -84,7 +84,7 @@ public struct IMEState: IMEStateProtocol {
     self.data = data
     self.type = type
     self.node = node
-    self.data.candidates = node.members.map { ("", $0.name) }
+    self.data.candidates = node.members.map { ([""], $0.name) }
   }
 }
 
@@ -107,7 +107,7 @@ extension IMEState {
     return result
   }
 
-  public static func ofAssociates(candidates: [(String, String)]) -> IMEState {
+  public static func ofAssociates(candidates: [([String], String)]) -> IMEState {
     var result = IMEState(type: .ofAssociates)
     result.candidates = candidates
     return result
@@ -132,7 +132,7 @@ extension IMEState {
     return result
   }
 
-  public static func ofCandidates(candidates: [(String, String)], displayTextSegments: [String], cursor: Int)
+  public static func ofCandidates(candidates: [([String], String)], displayTextSegments: [String], cursor: Int)
     -> IMEState
   {
     var result = IMEState(displayTextSegments: displayTextSegments, cursor: cursor)
@@ -178,7 +178,7 @@ extension IMEState {
     return result
   }
 
-  public var candidates: [(String, String)] {
+  public var candidates: [([String], String)] {
     get { data.candidates }
     set { data.candidates = newValue }
   }
diff --git a/Source/Modules/IMEStateData.swift b/Source/Modules/IMEStateData.swift
index 31a85948..c19f3f95 100644
--- a/Source/Modules/IMEStateData.swift
+++ b/Source/Modules/IMEStateData.swift
@@ -91,7 +91,7 @@ public struct IMEStateData: IMEStateDataProtocol {
 
   public var reading: String = ""
   public var markedReadings = [String]()
-  public var candidates = [(String, String)]()
+  public var candidates = [([String], String)]()
   public var textToCommit: String = ""
   public var tooltip: String = ""
   public var tooltipDuration: Double = 1.0
@@ -172,7 +172,7 @@ public struct IMEStateData: IMEStateDataProtocol {
 extension IMEStateData {
   public var doesUserPhraseExist: Bool {
     let text = displayedText.charComponents[markedRange].joined()
-    let joined = markedReadings.joined(separator: "-")
+    let joined = markedReadings.joined(separator: InputHandler.keySeparator)
     return LMMgr.checkIfUserPhraseExist(
       userPhrase: text, mode: IMEApp.currentInputMode, key: joined
     )
@@ -205,7 +205,7 @@ extension IMEStateData {
   }
 
   public var userPhraseKVPair: (String, String) {
-    let key = markedReadings.joined(separator: "-")
+    let key = markedReadings.joined(separator: InputHandler.keySeparator)
     let value = displayedText.charComponents[markedRange].joined()
     return (key, value)
   }
diff --git a/Source/Modules/InputHandler_Core.swift b/Source/Modules/InputHandler_Core.swift
index 90cb7f1d..9c1fe12d 100644
--- a/Source/Modules/InputHandler_Core.swift
+++ b/Source/Modules/InputHandler_Core.swift
@@ -22,6 +22,8 @@ public protocol InputHandlerProtocol {
   var currentUOM: vChewingLM.LMUserOverride { get set }
   var delegate: InputHandlerDelegate? { get set }
   var composer: Tekkon.Composer { get set }
+  var keySeparator: String { get }
+  static var keySeparator: String { get }
   var isCompositorEmpty: Bool { get }
   var isComposerUsingPinyin: Bool { get }
   func clear()
@@ -31,7 +33,7 @@ public protocol InputHandlerProtocol {
   func generateStateOfCandidates() -> IMEStateProtocol
   func generateStateOfInputting(sansReading: Bool) -> IMEStateProtocol
   func generateStateOfAssociates(withPair pair: Megrez.Compositor.KeyValuePaired) -> IMEStateProtocol
-  func consolidateNode(candidate: (String, String), respectCursorPushing: Bool, preConsolidate: Bool)
+  func consolidateNode(candidate: ([String], String), respectCursorPushing: Bool, preConsolidate: Bool)
   func updateUnigramData() -> Bool
 }
 
@@ -149,10 +151,10 @@ public class InputHandler: InputHandlerProtocol {
   /// - Parameter key: 給定的聯想詞的開頭字。
   /// - Returns: 抓取到的聯想詞陣列。
   /// 不會是 nil，但那些負責接收結果的函式會對空白陣列結果做出正確的處理。
-  func generateArrayOfAssociates(withPair pair: Megrez.Compositor.KeyValuePaired) -> [(String, String)] {
-    var arrResult: [(String, String)] = []
+  func generateArrayOfAssociates(withPair pair: Megrez.Compositor.KeyValuePaired) -> [([String], String)] {
+    var arrResult: [([String], String)] = []
     if currentLM.hasAssociatedPhrasesFor(pair: pair) {
-      arrResult = currentLM.associatedPhrasesFor(pair: pair).map { ("", $0) }
+      arrResult = currentLM.associatedPhrasesFor(pair: pair).map { ([""], $0) }
     }
     return arrResult
   }
@@ -223,7 +225,7 @@ public class InputHandler: InputHandlerProtocol {
         for (subPosition, key) in currentNode.keyArray.enumerated() {
           guard values.count > subPosition else { break }  // 防呆，應該沒有發生的可能性
           let thePair = Megrez.Compositor.KeyValuePaired(
-            key: key, value: values[subPosition]
+            keyArray: [key], value: values[subPosition]
           )
           compositor.overrideCandidate(thePair, at: position)
           position += 1
@@ -241,9 +243,9 @@ public class InputHandler: InputHandlerProtocol {
   ///   - respectCursorPushing: 若該選項為 true，則會在選字之後始終將游標推送至選字後的節錨的前方。
   ///   - consolidate: 在固化節點之前，先鞏固上下文。該選項可能會破壞在內文組字區內就地輪替候選字詞時的體驗。
   public func consolidateNode(
-    candidate: (String, String), respectCursorPushing: Bool = true, preConsolidate: Bool = false
+    candidate: ([String], String), respectCursorPushing: Bool = true, preConsolidate: Bool = false
   ) {
-    let theCandidate: Megrez.Compositor.KeyValuePaired = .init(key: candidate.0, value: candidate.1)
+    let theCandidate: Megrez.Compositor.KeyValuePaired = .init(keyArray: candidate.0, value: candidate.1)
 
     /// 必須先鞏固當前組字器游標上下文、以消滅意料之外的影響，但在內文組字區內就地輪替候選字詞時除外。
     if preConsolidate { consolidateCursorContext(with: theCandidate) }
@@ -284,7 +286,7 @@ public class InputHandler: InputHandlerProtocol {
   }
 
   /// 獲取候選字詞（包含讀音）陣列資料內容。
-  func generateArrayOfCandidates(fixOrder: Bool = true) -> [(String, String)] {
+  func generateArrayOfCandidates(fixOrder: Bool = true) -> [([String], String)] {
     /// 警告：不要對游標前置風格使用 nodesCrossing，否則會導致游標行為與 macOS 內建注音輸入法不一致。
     /// 微軟新注音輸入法的游標後置風格也是不允許 nodeCrossing 的。
     var arrCandidates: [Megrez.Compositor.KeyValuePaired] = {
@@ -301,7 +303,7 @@ public class InputHandler: InputHandlerProtocol {
 
     // 決定是否根據半衰記憶模組的建議來調整候選字詞的順序。
     if !prefs.fetchSuggestionsFromUserOverrideModel || prefs.useSCPCTypingMode || fixOrder {
-      return arrCandidates.map { ($0.key, $0.value) }
+      return arrCandidates.map { ($0.keyArray, $0.value) }
     }
 
     let arrSuggestedUnigrams: [(String, Megrez.Unigram)] = retrieveUOMSuggestions(apply: false)
@@ -310,8 +312,8 @@ public class InputHandler: InputHandlerProtocol {
     }
     arrCandidates = arrSuggestedCandidates.filter { arrCandidates.contains($0) } + arrCandidates
     arrCandidates = arrCandidates.deduplicated
-    arrCandidates = arrCandidates.stableSort { $0.key.split(separator: "-").count > $1.key.split(separator: "-").count }
-    return arrCandidates.map { ($0.key, $0.value) }
+    arrCandidates = arrCandidates.stableSort { $0.keyArray.count > $1.keyArray.count }
+    return arrCandidates.map { ($0.keyArray, $0.value) }
   }
 
   /// 向半衰引擎詢問可能的選字建議、且套用給組字器內的當前游標位置。
@@ -437,6 +439,10 @@ public class InputHandler: InputHandlerProtocol {
 
   // MARK: - Extracted methods and functions (Megrez).
 
+  public var keySeparator: String { compositor.separator }
+
+  public static var keySeparator: String { Megrez.Compositor.theSeparator }
+
   /// 就地增刪詞之後，需要就地更新游標上下文單元圖資料。
   public func updateUnigramData() -> Bool {
     let result = compositor.update(updateExisting: true)
diff --git a/Source/Modules/InputHandler_HandleCandidate.swift b/Source/Modules/InputHandler_HandleCandidate.swift
index c0fe4b67..bbcce410 100644
--- a/Source/Modules/InputHandler_HandleCandidate.swift
+++ b/Source/Modules/InputHandler_HandleCandidate.swift
@@ -173,12 +173,12 @@ extension InputHandler {
         ? currentLM.isThisCassetteKeyAllowed(key: input.text) : composer.inputValidityCheck(key: input.charCode)
 
       var shouldAutoSelectCandidate: Bool =
-        isInputValid || currentLM.hasUnigramsFor(key: customPunctuation)
-        || currentLM.hasUnigramsFor(key: punctuation)
+        isInputValid || currentLM.hasUnigramsFor(keyArray: [customPunctuation])
+        || currentLM.hasUnigramsFor(keyArray: [punctuation])
 
       if !shouldAutoSelectCandidate, input.isUpperCaseASCIILetterKey {
         let letter = "_letter_\(input.text)"
-        if currentLM.hasUnigramsFor(key: letter) { shouldAutoSelectCandidate = true }
+        if currentLM.hasUnigramsFor(keyArray: [letter]) { shouldAutoSelectCandidate = true }
       }
 
       if shouldAutoSelectCandidate {
diff --git a/Source/Modules/InputHandler_HandleComposition.swift b/Source/Modules/InputHandler_HandleComposition.swift
index d5322ded..59eb926b 100644
--- a/Source/Modules/InputHandler_HandleComposition.swift
+++ b/Source/Modules/InputHandler_HandleComposition.swift
@@ -53,7 +53,7 @@ extension InputHandler {
         theComposer.intonation.clear()
         // 檢查新的漢字字音是否在庫。
         let temporaryReadingKey = theComposer.getComposition()
-        if currentLM.hasUnigramsFor(key: temporaryReadingKey) {
+        if currentLM.hasUnigramsFor(keyArray: [temporaryReadingKey]) {
           compositor.dropKey(direction: .rear)
           walk()  // 這裡必須 Walk 一次、來更新目前被 walk 的內容。
           composer = theComposer
@@ -92,7 +92,7 @@ extension InputHandler {
         return handleCtrlCommandEnter()
       }
       // 向語言模型詢問是否有對應的記錄。
-      if !currentLM.hasUnigramsFor(key: readingKey) {
+      if !currentLM.hasUnigramsFor(keyArray: [readingKey]) {
         delegate.callError("B49C0979：語彙庫內無「\(readingKey)」的匹配記錄。")
 
         if prefs.keepReadingUponCompositionError {
@@ -140,14 +140,14 @@ extension InputHandler {
           case 2...: delegate.switchState(candidateState)
           case 1:
             let firstCandidate = candidateState.candidates.first!  // 一定會有，所以強制拆包也無妨。
-            let reading: String = firstCandidate.0
+            let reading: String = firstCandidate.0.joined(separator: compositor.separator)
             let text: String = firstCandidate.1
             delegate.switchState(IMEState.ofCommitting(textToCommit: text))
 
             if !prefs.associatedPhrasesEnabled {
               delegate.switchState(IMEState.ofEmpty())
             } else {
-              let associatedPhrases = generateStateOfAssociates(withPair: .init(key: reading, value: text))
+              let associatedPhrases = generateStateOfAssociates(withPair: .init(keyArray: [reading], value: text))
               delegate.switchState(associatedPhrases.candidates.isEmpty ? IMEState.ofEmpty() : associatedPhrases)
             }
           default: break
@@ -240,7 +240,7 @@ extension InputHandler {
         return handleCtrlCommandEnter()
       }
       // 向語言模型詢問是否有對應的記錄。
-      if !currentLM.hasUnigramsFor(key: calligrapher) {
+      if !currentLM.hasUnigramsFor(keyArray: [calligrapher]) {
         delegate.callError("B49C0979_Cassette：語彙庫內無「\(calligrapher)」的匹配記錄。")
 
         calligrapher.removeAll()
@@ -282,14 +282,14 @@ extension InputHandler {
           case 2...: delegate.switchState(candidateState)
           case 1:
             let firstCandidate = candidateState.candidates.first!  // 一定會有，所以強制拆包也無妨。
-            let reading: String = firstCandidate.0
+            let reading: String = firstCandidate.0.joined(separator: compositor.separator)
             let text: String = firstCandidate.1
             delegate.switchState(IMEState.ofCommitting(textToCommit: text))
 
             if !prefs.associatedPhrasesEnabled {
               delegate.switchState(IMEState.ofEmpty())
             } else {
-              let associatedPhrases = generateStateOfAssociates(withPair: .init(key: reading, value: text))
+              let associatedPhrases = generateStateOfAssociates(withPair: .init(keyArray: [reading], value: text))
               delegate.switchState(associatedPhrases.candidates.isEmpty ? IMEState.ofEmpty() : associatedPhrases)
             }
           default: break
diff --git a/Source/Modules/InputHandler_HandleInput.swift b/Source/Modules/InputHandler_HandleInput.swift
index 0f5d4d04..5dc352cb 100644
--- a/Source/Modules/InputHandler_HandleInput.swift
+++ b/Source/Modules/InputHandler_HandleInput.swift
@@ -190,7 +190,7 @@ extension InputHandler {
 
     if input.isSymbolMenuPhysicalKey, !input.isShiftHold, !input.isControlHold, state.type != .ofDeactivated {
       if input.isOptionHold {
-        if currentLM.hasUnigramsFor(key: "_punctuation_list") {
+        if currentLM.hasUnigramsFor(keyArray: ["_punctuation_list"]) {
           if isComposerOrCalligrapherEmpty, compositor.insertKey("_punctuation_list") {
             walk()
             // 一邊吃一邊屙（僅對位列黑名單的 App 用這招限制組字區長度）。
diff --git a/Source/Modules/InputHandler_HandleStates.swift b/Source/Modules/InputHandler_HandleStates.swift
index 46269acb..0a471a92 100644
--- a/Source/Modules/InputHandler_HandleStates.swift
+++ b/Source/Modules/InputHandler_HandleStates.swift
@@ -239,7 +239,7 @@ extension InputHandler {
   func handlePunctuation(_ customPunctuation: String) -> Bool {
     guard let delegate = delegate else { return false }
 
-    if !currentLM.hasUnigramsFor(key: customPunctuation) {
+    if !currentLM.hasUnigramsFor(keyArray: [customPunctuation]) {
       return false
     }
 
@@ -269,7 +269,7 @@ extension InputHandler {
       case 2...: delegate.switchState(candidateState)
       case 1:
         clear()  // 這句不要砍，因為下文可能會回呼 candidateState。
-        if let candidateToCommit: (String, String) = candidateState.candidates.first, !candidateToCommit.1.isEmpty {
+        if let candidateToCommit: ([String], String) = candidateState.candidates.first, !candidateToCommit.1.isEmpty {
           delegate.switchState(IMEState.ofCommitting(textToCommit: candidateToCommit.1))
         } else {
           delegate.switchState(candidateState)
@@ -337,13 +337,13 @@ extension InputHandler {
     var composed = ""
 
     for node in compositor.walkedNodes {
-      var key = node.key
+      var key = node.keyArray.joined(separator: "\t")
       if !prefs.cassetteEnabled {
         if prefs.inlineDumpPinyinInLieuOfZhuyin {
           key = Tekkon.restoreToneOneInZhuyinKey(target: key)  // 恢復陰平標記
           key = Tekkon.cnvPhonaToHanyuPinyin(target: key)  // 注音轉拼音
           key = Tekkon.cnvHanyuPinyinToTextbookStyle(target: key)  // 轉教科書式標調
-          key = key.replacingOccurrences(of: "-", with: " ")
+          key = key.replacingOccurrences(of: "\t", with: " ")
         } else {
           key = Tekkon.cnvZhuyinChainToTextbookReading(target: key, newSeparator: " ")
         }
@@ -706,7 +706,7 @@ extension InputHandler {
       return true
     }
 
-    let currentPaired = (currentNode.key, currentNode.value)
+    let currentPaired = (currentNode.keyArray, currentNode.value)
 
     var currentIndex = 0
     if !currentNode.isOverriden {
diff --git a/Source/Modules/LMMgr.swift b/Source/Modules/LMMgr.swift
index cd13d5f5..8fed9cbc 100644
--- a/Source/Modules/LMMgr.swift
+++ b/Source/Modules/LMMgr.swift
@@ -279,8 +279,8 @@ public class LMMgr {
     key unigramKey: String
   ) -> Bool {
     switch mode {
-      case .imeModeCHS: return lmCHS.hasKeyValuePairFor(key: unigramKey, value: userPhrase)
-      case .imeModeCHT: return lmCHT.hasKeyValuePairFor(key: unigramKey, value: userPhrase)
+      case .imeModeCHS: return lmCHS.hasKeyValuePairFor(key: [unigramKey], value: userPhrase)
+      case .imeModeCHT: return lmCHT.hasKeyValuePairFor(key: [unigramKey], value: userPhrase)
       case .imeModeNULL: return false
     }
   }
diff --git a/Source/Modules/SessionCtl_Delegates.swift b/Source/Modules/SessionCtl_Delegates.swift
index 15c5bc10..7d66545d 100644
--- a/Source/Modules/SessionCtl_Delegates.swift
+++ b/Source/Modules/SessionCtl_Delegates.swift
@@ -57,7 +57,8 @@ extension SessionCtl: InputHandlerDelegate {
     // 該臨時資料記錄會在接下來的語言模組資料重載過程中被自動清除。
     let temporaryScore: Double = SessionCtl.areWeNerfing ? -114.514 : 0
     LMMgr.currentLM.insertTemporaryData(
-      key: rawPair.0, unigram: .init(value: rawPair.1, score: temporaryScore), isFiltering: SessionCtl.areWeNerfing
+      keyArray: [rawPair.0], unigram: .init(value: rawPair.1, score: temporaryScore),
+      isFiltering: SessionCtl.areWeNerfing
     )
     // 開始針對使用者半衰模組的清詞處理
     LMMgr.bleachSpecifiedSuggestions(targets: [valueCurrent], mode: IMEApp.currentInputMode)
@@ -95,12 +96,12 @@ extension SessionCtl: CtlCandidateDelegate {
     PrefMgr.shared.useIMKCandidateWindow ? "123456789" : PrefMgr.shared.candidateKeys
   }
 
-  public func candidatePairs(conv: Bool = false) -> [(String, String)] {
+  public func candidatePairs(conv: Bool = false) -> [([String], String)] {
     if !state.isCandidateContainer || state.candidates.isEmpty { return [] }
-    if !conv || PrefMgr.shared.cns11643Enabled || state.candidates[0].0.contains("_punctuation") {
+    if !conv || PrefMgr.shared.cns11643Enabled || state.candidates[0].0.joined().contains("_punctuation") {
       return state.candidates
     }
-    let convertedCandidates: [(String, String)] = state.candidates.map { theCandidatePair -> (String, String) in
+    let convertedCandidates: [([String], String)] = state.candidates.map { theCandidatePair -> ([String], String) in
       let theCandidate = theCandidatePair.1
       let theConverted = ChineseConverter.kanjiConversionIfRequired(theCandidate)
       let result = (theCandidate == theConverted) ? theCandidate : "\(theConverted)(\(theCandidate))"
@@ -139,7 +140,7 @@ extension SessionCtl: CtlCandidateDelegate {
         // 此時是逐字選字模式，所以「selectedValue.1」是單個字、不用追加處理。
         if PrefMgr.shared.associatedPhrasesEnabled {
           let associates = inputHandler.generateStateOfAssociates(
-            withPair: .init(key: selectedValue.0, value: selectedValue.1)
+            withPair: .init(keyArray: selectedValue.0, value: selectedValue.1)
           )
           switchState(associates.candidates.isEmpty ? IMEState.ofEmpty() : associates)
         } else {
@@ -162,7 +163,7 @@ extension SessionCtl: CtlCandidateDelegate {
       }
       if PrefMgr.shared.associatedPhrasesEnabled {
         let associates = inputHandler.generateStateOfAssociates(
-          withPair: .init(key: selectedValue.0, value: String(valueKept))
+          withPair: .init(keyArray: selectedValue.0, value: String(valueKept))
         )
         if !associates.candidates.isEmpty {
           switchState(associates)
@@ -204,7 +205,7 @@ extension SessionCtl: CtlCandidateDelegate {
     // 該臨時資料記錄會在接下來的語言模組資料重載過程中被自動清除。
     let temporaryScore: Double = (action == .toNerf) ? -114.514 : 0
     LMMgr.currentLM.insertTemporaryData(
-      key: rawPair.0, unigram: .init(value: rawPair.1, score: temporaryScore), isFiltering: action == .toFilter
+      keyArray: rawPair.0, unigram: .init(value: rawPair.1, score: temporaryScore), isFiltering: action == .toFilter
     )
 
     // 開始針對使用者半衰模組的清詞處理
diff --git a/Source/Modules/SessionCtl_IMKCandidatesData.swift b/Source/Modules/SessionCtl_IMKCandidatesData.swift
index 94a45033..f728dc40 100644
--- a/Source/Modules/SessionCtl_IMKCandidatesData.swift
+++ b/Source/Modules/SessionCtl_IMKCandidatesData.swift
@@ -21,17 +21,19 @@ extension SessionCtl {
     var arrResult = [String]()
 
     // 注意：下文中的不可列印字元是用來方便在 IMEState 當中用來分割資料的。
-    func handleIMKCandidatesPrepared(_ candidates: [(String, String)], prefix: String = "") {
+    func handleIMKCandidatesPrepared(_ candidates: [([String], String)], prefix: String = "") {
+      guard let separator = inputHandler?.keySeparator else { return }
       for theCandidate in candidates {
         let theConverted = ChineseConverter.kanjiConversionIfRequired(theCandidate.1)
         var result = (theCandidate.1 == theConverted) ? theCandidate.1 : "\(theConverted)\u{1A}(\(theCandidate.1))"
         if arrResult.contains(result) {
           let reading: String =
             PrefMgr.shared.cassetteEnabled
-            ? theCandidate.0
+            ? theCandidate.0.joined(separator: separator)
             : (PrefMgr.shared.showHanyuPinyinInCompositionBuffer
-              ? Tekkon.cnvPhonaToHanyuPinyin(target: Tekkon.restoreToneOneInZhuyinKey(target: theCandidate.0))
-              : theCandidate.0)
+              ? Tekkon.cnvPhonaToHanyuPinyin(
+                target: Tekkon.restoreToneOneInZhuyinKey(target: theCandidate.0.joined(separator: separator)))
+              : theCandidate.0.joined(separator: separator))
           result = "\(result)\u{17}(\(reading))"
         }
         arrResult.append(prefix + result)
@@ -82,15 +84,18 @@ extension SessionCtl {
     var indexDeducted = 0
 
     // 注意：下文中的不可列印字元是用來方便在 IMEState 當中用來分割資料的。
-    func handleIMKCandidatesSelected(_ candidates: [(String, String)], prefix: String = "") {
+    func handleIMKCandidatesSelected(_ candidates: [([String], String)], prefix: String = "") {
+      guard let separator = inputHandler?.keySeparator else { return }
       for (i, neta) in candidates.enumerated() {
         let theConverted = ChineseConverter.kanjiConversionIfRequired(neta.1)
         let netaShown = (neta.1 == theConverted) ? neta.1 : "\(theConverted)\u{1A}(\(neta.1))"
         let reading: String =
           PrefMgr.shared.cassetteEnabled
-          ? neta.0
+          ? neta.0.joined(separator: separator)
           : (PrefMgr.shared.showHanyuPinyinInCompositionBuffer
-            ? Tekkon.cnvPhonaToHanyuPinyin(target: Tekkon.restoreToneOneInZhuyinKey(target: neta.0)) : neta.0)
+            ? Tekkon.cnvPhonaToHanyuPinyin(
+              target: Tekkon.restoreToneOneInZhuyinKey(target: neta.0.joined(separator: separator)))
+            : neta.0.joined(separator: separator))
         let netaShownWithPronunciation = "\(netaShown)\u{17}(\(reading))"
         if candidateString == prefix + netaShownWithPronunciation {
           indexDeducted = i
@@ -104,7 +109,7 @@ extension SessionCtl {
     }
 
     // 分類符號選單不會出現同符異音項、不需要康熙 / JIS 轉換，所以使用簡化過的處理方式。
-    func handleSymbolCandidatesSelected(_ candidates: [(String, String)]) {
+    func handleSymbolCandidatesSelected(_ candidates: [([String], String)]) {
       for (i, neta) in candidates.enumerated() {
         if candidateString == neta.1 {
           indexDeducted = i