Elision is very simply the omission of certain sounds in certain contexts. The most important occurrences of this phenomenon regard:
1) Alveolar consonants /t/ and /d/ when 'sandwiched' between two consonants (CONS – t/d – CONS), e.g.
|The next day||/ðə ˈneks(t) ˈdeɪ/|
|The last car||/ðə ˈlɑːs(t) ˈkɑː/|
|Hold the dog!||/ˈhəʊl(d) ðə ˈdɒg/|
|Send Frank a card||/sen(d) ˈfræŋk ə ˈkɑːd/|
This can also take place within affricates /ʧ/ and /ʤ/ when preceded by a consonant, e.g. ʃʒ
|lunchtime||/ˈlʌnʧtaɪm/ > /ˈlʌnʃtaɪm/|
|strange days||/ˈstreɪnʤˈdeɪz/ > /ˈstreɪnʒˈdeɪz/|
The phoneme /t/ is a fundamental part of the negative particle not, the possibility of it being elided makes the non-native speaker's life more difficult. Consider the negative of can – if followed by a consonant the /t/ may easily disappear and the only difference between the positive and the negative is a different, longer vowel sound in the second:
|I can speak Spanish||/aɪ kən ˈspiːk ˈspænɪʃ/|
|I can't speak Spanish||/aɪ ˈkɑːn(t) ˈspiːk ˈspænɪʃ/|
Note that when can't is followed by a vowel, e.g. I can't eat, the /t/ is not elided.
2) A second form involves the omission of the schwa /ə/ before liquids /l/ and /r/, e.g.
|secretary||/ˈsekrətəri/ > /ˈsekrətri/|
|camera||/ˈkæmərə/ > /ˈkæmrə/|
|memory||/ˈmeməri/ > /ˈmemri/|