/**
 * Thai Text Utilities - Handle Thai combining characters
 *
 * Thai vowels and tone marks are combining characters that must
 * stay attached to their base consonant.
 */
/**
 * Check if a character is a Thai vowel or diacritic
 *
 * Thai Unicode ranges:
 * - 0x0E30-0x0E3A: Vowels (Sara) and tone marks
 * - 0x0E40-0x0E44: Leading vowels
 * - 0x0E47-0x0E4E: Tone marks and other diacritics
 */
export declare function isThaiVowelOrDiacritic(char: string): boolean;
/**
 * Check if text contains ONLY Thai vowels/diacritics
 * IMPORTANT: Returns false if text contains any whitespace
 * This prevents merging parts that have spaces (which would lose the space)
 */
export declare function isOnlyThaiVowels(text: string): boolean;
/**
 * Merge Thai vowels/diacritics with the previous word part
 * This prevents vowels from floating separately from their consonants
 *
 * @param parts Array of lyric parts
 * @returns Merged array where vowel-only parts are combined with previous parts
 */
export declare function mergeThaiVowelsWithPreviousParts<T extends {
    text: string;
}>(parts: T[]): T[];
/**
 * Normalize Thai text for consistent rendering
 * Applies Unicode normalization (NFC) to ensure combining characters
 * are properly composed with their base characters
 */
export declare function normalizeThaiText(text: string): string;
/**
 * Split Thai text by words while keeping vowels attached
 * This is a simple implementation that respects Thai combining characters
 */
export declare function splitThaiText(text: string): string[];