The Sounds of Language
The sounds we produce can be described in terms of their physical properties and in terms of how they are articulated. The acoustic details of speech sounds are studied as phonetics. The description of sounds in terms of how they are produced is known as phonology. Think about how to produce the ‘t’ at the beginning of the word ‘tin.’ If you are native speaker of English, you will produce a small burst of air as you produce the ‘t’. This is not the case when you produce the ‘t’ in the word ‘sit.’ The ‘t’ in ‘tin’ is aspirated and the ‘t’ in ‘sit’ is unaspirated. Even if you produce the ‘t’ without aspiration, it may sound odd but doesn’t change the meaning of the word in English. We will call these different sounds phones. However, in some languages (such as Hindi), aspiration does change meaning. Therefore, in Hindi there is a distinction between unaspirated [b] in [bɑːluː] ‘sand’ and aspirated [bʰ] in [bʰɑːluː] ‘bear’. As English doesn’t differentiate between aspirated and unaspirated sounds, Mowgli’s bear buddy in Rudyard Kipling’s ‘The Jungle Book’ is simply called Baloo. Similarly, the ‘gh’ in Bagheera is an aspirated [ɡʰ] sound which is not pronounced as such in English. When we write out a phone in linguistics, we place them between two square brackets (as seen above).
The smallest sound unit in a language is known as a phoneme. In English, the aspirated and unaspirated ‘t’ sounds are both considered one phoneme as they are not distinguished by speakers of that language. When such sounds occur without being differentiated by speakers of a languages, they are known as allophones. However, in Hindi the aspirated and unaspirated ‘t’ sounds are separate phonemes. When we write out phonemes in linguistics, we place them between two forward slashes. So, a phonemic description of the word ‘pin’ would look like /pɪn/, while a phonetic description would look like [pʰɪn].
In order to discover all the phonemes in a language, we often employ minimal pairs. Two words that differ from each other in just one phoneme are know as minimal pairs. Consider ‘kit’ and ‘kid’. Substituting ‘t’ for ‘d’ changes the meaning of the word, but changing [kɪt] with [kɪth] would not. Therefore, /t/ and /d/ are phonemes in English and [t] and [th] are phones.