Are there any PG Diploma or short-term courses for speech therapist?

Yes, there are several PG Diploma and short term courses available in india for speech therapists 

Here are some courses like -

1. Post Graduate Diploma in Auditory Verbal Therapy (PGDAVT):
2. Post Graduate Diploma in Clinical Linguistics for Speech-Language Pathology (PGDCLP)
3. Diploma in Audiology and Speech