for learners to aim at, and to act as a basis for description in textbooks and classroom materials. RP has been the traditional choice for teachers and learners of British English. However, the choice of pronunciation model is difficult, and the adoption of RP is in many ways problematic. Phonology Consonants Nasals and liquids (, , , , ) may be syllabic in unstressed syllables. The consonant in RP is generally a postalveolar approximant, which would normally be expressed with the sign in the International Phonetic Alphabet, but the sign is nonetheless traditionally used for RP in most of the literature on the topic. Voiceless plosives (, , , ) are aspirated at the beginning of a syllable, unless a completely unstressed vowel follows. (For example, the is aspirated in "impasse", with primary stress on "-passe", but not "compass", where "-pass" has no stress.) Aspiration does not occur when precedes in the same syllable, as in "spot" or "stop". When a sonorant , , , or follows, this aspiration is indicated by partial devoicing of the sonorant. is a fricative when devoiced. Syllable final , , , and may be either preceded by a glottal stop (glottal reinforcement) or, in the case of , fully replaced by a glottal stop, especially before a syllabic nasal (bitten ). The glottal stop may be realised as creaky voice; thus, an alternative phonetic transcription of attempt could be . As in other varieties of English, voiced plosives (, , , ) are partly or even fully devoiced at utterance boundaries or adjacent to voiceless consonants. The voicing distinction between voiced and voiceless sounds is reinforced by a number of other differences, with the result that the two of consonants can clearly be distinguished even in the presence of devoicing of voiced sounds: Aspiration of voiceless consonants syllable-initially. Glottal reinforcement of /p, t, k, tʃ/ syllable-finally. Shortening of vowels before voiceless consonants. As a result, some authors prefer to use the terms "fortis" and "lenis" in place of "voiceless" and "voiced". However, the latter are traditional and in more frequent usage. The voiced dental fricative () is more often a weak dental plosive; the sequence is often realised as (a long dental nasal). has velarised allophone () in the syllable rhyme. becomes voiced () between voiced sounds. Vowels Examples of short vowels: in kit, mirror and rabbit, in foot and cook, in dress and