The long ‘a’ is the fifth sound in the International Phonetics Association’s (IPA) list of vowels. When you look at the vowel quadrilateral, it is a back open sound. Like the long ‘e’, /a:/ is a universal sound. In Nigeria, all the major dialects have the vowel, so it is not a difficult sound for Nigerians to articulate. If you have ever visited a dentist, then you said /a:/. Also, the sound is said each time you exclaim “Ah!”
As has also been noted with the long ‘e’, the only difference that can be seen between the English /a:/ and the /a/ in our dialects’ is the variation in length. The English /a:/ is a long sound and so it is always loud.
How to teach the long ‘a’ sound to beginning learners
Show an item that contains the long ‘a’ sound. Use an item everyone is familiar with. For example, a picture of a shark.
Ask if anyone can spell the word. After the word is spelt underline the letters ‘ar’ in the word and ask if anyone can say it.
Explain that the letters ‘ar’ says the long ‘a’ and write out vowel /a:/. Give other word examples (barn, mark, sharp) and explain that when the learners see the ‘ar’ in words, it will most likely say /a:/.
Ask the learners to supply more /a:/ word examples. They will supply a mix of words. Some are spelt with other letters; some may not contain the vowel. Use a dictionary to show them how to confirm whether a word has the vowel or not.
Have the learners say /a:/ in isolation and then practice writing it down in their notebooks.
Word Examples for the long ‘a’ sound
Calm /ka:m/ Palm /pa;m/
Farm /fa:m/ Psalm /sa:m/
Barn /ba:n/ Path /pa:θ/
Pass /pa:s/ Chart /t∫a:t/
Bath /baθ/ Father /fɑːðə:/