यह is singular, and it is pronounced ये, always. ये is plural, and it is pronounced the same as the singular - ये. वह is singular, and it is pronounced वो. वे is plural, and it is pronounced as it is spelled - वे. वे, the plural form, however, is generally not used. Instead the singular वह(which is pronounced as वो) is used, both the spelling and the pronunciation. It might be a little strange because Hindi is a phonetic language. Maybe in the past people used to pronounce these two words phonetically and if that's the case, then it's possible that the pronunciation of these words might have undergone some changes over the years. Hope this helps! Have a nice day 😃

Pronounciation is same as written. वह vah a being shorter length यह yah However in spoken वो is used. I think Bihar region people speak वह as it is. Both are ok. I never use वह, यह in speaking. And when i speak ये, वो I really mean it as ये, वो respectivelt. Not वह, यह यह, वह is old fashioned or still prevelant in some regions.

vah for that and yah for this

Wah and Yah