[anuragz]

HI,
As i have a slight lisp trouble so i'v read a lot about 'how to produce s sound'. But i m not able to figure out that what is the exact position to produce 's' sound ? on which alveolar ridge should be the tongue on ? upper or lower ? My natural tongue position for 's' is on upper alveolar ridge but it does not comes as sharp as it should be. But when i practice words with 's' sound by touching my tongue on lower alveolar ridge i produce much sharper 's' sound. But actually i m confused on how to produce /ts/, /ds/,(eg. baTS, paDS, poTS, STates) sounds as the tongue can not travel instantly from upper to lower alveolar ridge(/t/- upper, /s/- lower alveolar ridge). Can you plz clerify what should be the natural tongue position for /s/,/z/, /sh/, /ts/,/ds/.