export declare function getPhoneSubstitutionCost1(ipa1: string, ipa2: string): 0 | 1;
export declare function getPhoneSubstitutionCost2(ipa1: string, ipa2: string): 0 | 1 | 0.5;
export declare function getPhoneSubstitutionCost3(ipa1: string, ipa2: string): 0 | 1 | 0.5 | 0.75;
export declare function isKnownSymbol(ipa: string): boolean;
export declare function isConsonant(ipa: string): boolean;
export declare function isVowel(ipa: string): boolean;
export declare function isPlosiveOrNasal(ipa: string): boolean;
export declare function isTrillTapOrFlap(ipa: string): boolean;
export declare function isFricativeLike(ipa: string): boolean;
export declare function isApproximantLike(ipa: string): boolean;
export declare function isPlosive(ipa: string): boolean;
export declare function isNasal(ipa: string): boolean;
export declare function isTrill(ipa: string): boolean;
export declare function isTapOrFlap(ipa: string): boolean;
export declare function isFricative(ipa: string): boolean;
export declare function isLateralFricative(ipa: string): boolean;
export declare function isAffricate(ipa: string): boolean;
export declare function isApproximant(ipa: string): boolean;
export declare function isLateralApproximant(ipa: string): boolean;