/**
 * RP (Received Pronunciation) post-processing for English G2P output.
 *
 * The base English G2P returns General American IPA. This module turns
 * that output into a reasonable RP / Southern Standard British rendering
 * via rule-based transformation — no separate dictionary file is loaded
 * (which would roughly double the package size).
 *
 * Coverage is intentionally conservative:
 *   - non-rhoticity (drop coda /ɹ/, lengthen the preceding vowel)
 *   - NURSE split: stressed /ɝ/ → /ɜː/, unstressed → /ə/
 *   - SQUARE / NEAR / CURE diphthongs from /Vɹ/ pairs
 *   - FIRE / POWER from diphthong + /ɹ/
 *   - French -age borrowings: lengthen final stressed vowel + drop /d/
 *   - yod retention after word-initial /s/ (sue, suit, super, …)
 *
 * Words whose RP form genuinely can't be derived by rule (schedule,
 * tomato, herb, …) live in `src-data/en-gb/lexical.json`, not in this
 * source file.
 */
/**
 * Convert American-English IPA to RP IPA for the given word. Looks up
 * lexical shibboleths first; falls back to rule-based transformation.
 */
export declare function transformAmericanToRP(word: string, ipaUS: string): string;