substituted by the glottal stop) as in button, but many speakers preserve at least an unreleased coronal stop . In addition, the following allophones of /t/ are found in (at least) some dialects of American(ised) English; flapped as in American English water, nasal(ized) flapped as in American English winter. unreleased as in American English cat, but other dialects preserve the released , or substitute the glottal stop . However, speakers may become aware of the differences iffor examplethey contrast the pronunciations of the following words: Night rate: unreleased (without a word space between and ) Nitrate: aspirated or retracted A flame that is held in front of the lips while those words are spoken flickers more for the aspirated nitrate than for the unaspirated night rate. The difference can also be felt by holding the hand in front of the lips. For a Mandarin-speaker, for whom and are separate phonemes, the English distinction is much more obvious than for an English-speaker, who has learned since childhood to ignore the distinction. One may notice the (dialect-dependent) allophones of English such as the (palatal) alveolar "light" of leaf as opposed to the velar alveolar "dark" in feel found in the U.S. and Southern England. The difference is much more obvious to a Turkish-speaker, for whom and are separate phonemes, than to an English speaker, for whom they are allophones of a single phoneme. These descriptions are more sequentially broken down in the next section. Rules for English consonant allophones Peter Ladefoged, a renowned phonetician, clearly explains the consonant allophones of English in a precise list of statements to illustrate the language behavior. Some of these rules apply to all the consonants of English; the first item on the list deals with consonant length, items 2 through 18 apply to only selected groups of consonants, and the last item deals with the quality of a consonant. These descriptive rules are as follows: Consonants are longer when at the end of a phrase. This can be easily tested by recording a speaker saying a sound like “bib”, then comparing the forward and backward playback of the recording. One will find that the backward playback does not sound like the forward playback because the production of what is expected to be the same sound is not identical. Voiceless stops are aspirated when they come at the beginning of a syllable, such as in words like