Need help in developing plural to singular words

Question

Hello,

please help me in one problem. my requirement is user will put plural word in text box which is need to convert it in singular and again pass it the user.
for this i googling many hours din't get solution for my problem. and one more thing is there any service, dll, api available in which they are creating same function i'll just use it in my program.

Thanks in advance,
Omkar.