differences between long /i:/ and short /i/

Many students have problems distinguishing two vowels /i:/, sometimes written as /iy/ (e.g. – cheese and feed), and /i/ (e.g. – bit and kit).

What’s the difference? /iy/ is longer.  This vowel begins as an /i/ and then it becomes a /y/.  For the /y/ portion, the lips are stretched out if you say it carefully.  /i/ is shorter.  There is no change in the quality of this vowel, so the lips are not stretched out at the end.

Some minimal pairs (word pairs which are the same except for one sound) for these vowels are the following (the first word in the pair is /iy/ and the second one is /i/):

bead/bid     lead/lid      green/grin      bean/bin

To see the difference in lip position and to hear the differences between these vowels, please watch this video: