import type { VoiceEngine } from '../../../engines/VoiceEngine';
import type { VoiceServiceOptions, VoiceServiceOptionsUpdate } from '../../VoiceService';
export declare function applyOptionsToEngine(engine: VoiceEngine, options: VoiceServiceOptions): void;
export declare function getAllowedUpdateKeys(engineType: VoiceServiceOptions['engineType']): readonly string[];
export declare function mergeOptionsForEngine(current: VoiceServiceOptions, update: VoiceServiceOptionsUpdate): VoiceServiceOptions;