diff --git a/pkg/i18n/i18n.go b/pkg/i18n/i18n.go
index 68d7b768..2f48cac9 100644
--- a/pkg/i18n/i18n.go
+++ b/pkg/i18n/i18n.go
@@ -185,137 +185,6 @@ func _(messageID string, args ...any) string {
 	return messageID
 }
 
-// --- JSON parsing helpers ---
-
-// flatten recursively flattens nested maps into dot-notation keys.
-func flatten(prefix string, data map[string]any, out map[string]Message) {
-	flattenWithGrammar(prefix, data, out, nil)
-}
-
-// flattenWithGrammar recursively flattens nested maps and extracts grammar data.
-func flattenWithGrammar(prefix string, data map[string]any, out map[string]Message, grammar *GrammarData) {
-	for key, value := range data {
-		fullKey := key
-		if prefix != "" {
-			fullKey = prefix + "." + key
-		}
-
-		switch v := value.(type) {
-		case string:
-			out[fullKey] = Message{Text: v}
-
-		case map[string]any:
-			// Check if this is a verb form object
-			// Grammar data lives under "gram.*" (a nod to Gram - grandmother)
-			if grammar != nil && isVerbFormObject(v) {
-				verbName := key
-				if strings.HasPrefix(fullKey, "gram.verb.") {
-					verbName = strings.TrimPrefix(fullKey, "gram.verb.")
-				}
-				forms := VerbForms{}
-				if base, ok := v["base"].(string); ok {
-					_ = base // base form stored but not used in VerbForms
-				}
-				if past, ok := v["past"].(string); ok {
-					forms.Past = past
-				}
-				if gerund, ok := v["gerund"].(string); ok {
-					forms.Gerund = gerund
-				}
-				grammar.Verbs[strings.ToLower(verbName)] = forms
-				continue
-			}
-
-			// Check if this is a noun form object
-			if grammar != nil && isNounFormObject(v) {
-				nounName := key
-				if strings.HasPrefix(fullKey, "gram.noun.") {
-					nounName = strings.TrimPrefix(fullKey, "gram.noun.")
-				}
-				forms := NounForms{}
-				if one, ok := v["one"].(string); ok {
-					forms.One = one
-				}
-				if other, ok := v["other"].(string); ok {
-					forms.Other = other
-				}
-				if gender, ok := v["gender"].(string); ok {
-					forms.Gender = gender
-				}
-				grammar.Nouns[strings.ToLower(nounName)] = forms
-				continue
-			}
-
-			// Check if this is an article object
-			if grammar != nil && fullKey == "gram.article" {
-				if indef, ok := v["indefinite"].(map[string]any); ok {
-					if def, ok := indef["default"].(string); ok {
-						grammar.Articles.IndefiniteDefault = def
-					}
-					if vowel, ok := indef["vowel"].(string); ok {
-						grammar.Articles.IndefiniteVowel = vowel
-					}
-				}
-				if def, ok := v["definite"].(string); ok {
-					grammar.Articles.Definite = def
-				}
-				continue
-			}
-
-			// Check if this is a punctuation rules object
-			if grammar != nil && fullKey == "gram.punct" {
-				if label, ok := v["label"].(string); ok {
-					grammar.Punct.LabelSuffix = label
-				}
-				if progress, ok := v["progress"].(string); ok {
-					grammar.Punct.ProgressSuffix = progress
-				}
-				continue
-			}
-
-			// Check if this is a base word in gram.word.*
-			if grammar != nil && strings.HasPrefix(fullKey, "gram.word.") {
-				wordKey := strings.TrimPrefix(fullKey, "gram.word.")
-				// v could be a string or a nested object
-				if str, ok := value.(string); ok {
-					if grammar.Words == nil {
-						grammar.Words = make(map[string]string)
-					}
-					grammar.Words[strings.ToLower(wordKey)] = str
-				}
-				continue
-			}
-
-			// Check if this is a plural object (has CLDR plural category keys)
-			if isPluralObject(v) {
-				msg := Message{}
-				if zero, ok := v["zero"].(string); ok {
-					msg.Zero = zero
-				}
-				if one, ok := v["one"].(string); ok {
-					msg.One = one
-				}
-				if two, ok := v["two"].(string); ok {
-					msg.Two = two
-				}
-				if few, ok := v["few"].(string); ok {
-					msg.Few = few
-				}
-				if many, ok := v["many"].(string); ok {
-					msg.Many = many
-				}
-				if other, ok := v["other"].(string); ok {
-					msg.Other = other
-				}
-				out[fullKey] = msg
-			} else {
-				// Recurse into nested object
-				flattenWithGrammar(fullKey, v, out, grammar)
-			}
-		}
-	}
-}
-
 func detectLanguage(supported []language.Tag) string {
 	langEnv := os.Getenv("LANG")
 	if langEnv == "" {
diff --git a/pkg/i18n/mutate.go b/pkg/i18n/mutate.go
new file mode 100644
index 00000000..1f365204
--- /dev/null
+++ b/pkg/i18n/mutate.go
@@ -0,0 +1,133 @@
+// Package i18n provides internationalization for the CLI.
+package i18n
+
+import "strings"
+
+// flatten recursively flattens nested maps into dot-notation keys.
+func flatten(prefix string, data map[string]any, out map[string]Message) {
+	flattenWithGrammar(prefix, data, out, nil)
+}
+
+// flattenWithGrammar recursively flattens nested maps and extracts grammar data.
+func flattenWithGrammar(prefix string, data map[string]any, out map[string]Message, grammar *GrammarData) {
+	for key, value := range data {
+		fullKey := key
+		if prefix != "" {
+			fullKey = prefix + "." + key
+		}
+
+		switch v := value.(type) {
+		case string:
+			out[fullKey] = Message{Text: v}
+
+		case map[string]any:
+			// Check if this is a verb form object
+			// Grammar data lives under "gram.*" (a nod to Gram - grandmother)
+			if grammar != nil && isVerbFormObject(v) {
+				verbName := key
+				if strings.HasPrefix(fullKey, "gram.verb.") {
+					verbName = strings.TrimPrefix(fullKey, "gram.verb.")
+				}
+				forms := VerbForms{}
+				if base, ok := v["base"].(string); ok {
+					_ = base // base form stored but not used in VerbForms
+				}
+				if past, ok := v["past"].(string); ok {
+					forms.Past = past
+				}
+				if gerund, ok := v["gerund"].(string); ok {
+					forms.Gerund = gerund
+				}
+				grammar.Verbs[strings.ToLower(verbName)] = forms
+				continue
+			}
+
+			// Check if this is a noun form object
+			if grammar != nil && isNounFormObject(v) {
+				nounName := key
+				if strings.HasPrefix(fullKey, "gram.noun.") {
+					nounName = strings.TrimPrefix(fullKey, "gram.noun.")
+				}
+				forms := NounForms{}
+				if one, ok := v["one"].(string); ok {
+					forms.One = one
+				}
+				if other, ok := v["other"].(string); ok {
+					forms.Other = other
+				}
+				if gender, ok := v["gender"].(string); ok {
+					forms.Gender = gender
+				}
+				grammar.Nouns[strings.ToLower(nounName)] = forms
+				continue
+			}
+
+			// Check if this is an article object
+			if grammar != nil && fullKey == "gram.article" {
+				if indef, ok := v["indefinite"].(map[string]any); ok {
+					if def, ok := indef["default"].(string); ok {
+						grammar.Articles.IndefiniteDefault = def
+					}
+					if vowel, ok := indef["vowel"].(string); ok {
+						grammar.Articles.IndefiniteVowel = vowel
+					}
+				}
+				if def, ok := v["definite"].(string); ok {
+					grammar.Articles.Definite = def
+				}
+				continue
+			}
+
+			// Check if this is a punctuation rules object
+			if grammar != nil && fullKey == "gram.punct" {
+				if label, ok := v["label"].(string); ok {
+					grammar.Punct.LabelSuffix = label
+				}
+				if progress, ok := v["progress"].(string); ok {
+					grammar.Punct.ProgressSuffix = progress
+				}
+				continue
+			}
+
+			// Check if this is a base word in gram.word.*
+			if grammar != nil && strings.HasPrefix(fullKey, "gram.word.") {
+				wordKey := strings.TrimPrefix(fullKey, "gram.word.")
+				// v could be a string or a nested object
+				if str, ok := value.(string); ok {
+					if grammar.Words == nil {
+						grammar.Words = make(map[string]string)
+					}
+					grammar.Words[strings.ToLower(wordKey)] = str
+				}
+				continue
+			}
+
+			// Check if this is a plural object (has CLDR plural category keys)
+			if isPluralObject(v) {
+				msg := Message{}
+				if zero, ok := v["zero"].(string); ok {
+					msg.Zero = zero
+				}
+				if one, ok := v["one"].(string); ok {
+					msg.One = one
+				}
+				if two, ok := v["two"].(string); ok {
+					msg.Two = two
+				}
+				if few, ok := v["few"].(string); ok {
+					msg.Few = few
+				}
+				if many, ok := v["many"].(string); ok {
+					msg.Many = many
+				}
+				if other, ok := v["other"].(string); ok {
+					msg.Other = other
+				}
+				out[fullKey] = msg
+			} else {
+				// Recurse into nested object
+				flattenWithGrammar(fullKey, v, out, grammar)
+			}
+		}
+	}
+}