Final answer:
To label phonemes, use slashes // and for allophones, use brackets []. Phonemes are basic sound units differing meaning, while allophones are variations not altering meaning. For vowel lengths, use IPA symbols to indicate short or long sounds.
Step-by-step explanation:
To label phonemes and allophones, one must understand the difference between the two. Phonemes are the basic units of sound that can change the meaning of a word within a particular language. For example, switching the phoneme /p/ to /b/ in the word 'pat' changes it to 'bat'. Allophones, on the other hand, are variations of phonemes that do not change the word's meaning and are often influenced by their surrounding sounds. For instance, the 'l' sound in 'lip' versus 'pill' are allophones of the phoneme /l/.
To label a sound as a phoneme, use the slashes //, such as /p/ for the phoneme 'p'. When labeling allophones, use brackets [], such as [pʰ] for the aspirated 'p' in 'pat'. Be aware of letters that can spell different sounds, like the 'g' in 'goat' and 'giraffe', and remember that orthographic representation (spelling) can differ from phonetic realization.
For labeling vowels and consonants with regards to their vowel length (i.e., short or long vowels), phoneme labeling typically uses symbols from the International Phonetic Alphabet (IPA), such as [a] for the short sound 'a', and [ā] or [aː] for the long sound 'a'.