Sounds of letters often have ‘allophones’ which are slight variations on the same sound. The ‘p’ in ‘pot’ and ‘spot’ are slightly different. The ‘l”s in ‘lateral’ are also slightly different. The letters can actually sometimes sound like other sounds associated with different letters. What happens when you say the word ‘oil’ and then play it back backwards? it sounds like OIL! YEP…it really does, the word does sound slightly different but if you just heard it you would say that the person is speaking the word OIL.

(The Great Courses – Understanding Linguistics: The Science of Language)