Most Hindu scriptures, prayers, and mantras are written in Sanskrit. Sanskrit was considered the language of the gods. Sanskrit was the only language used during ancient times, but later on, many languages were born out of Sanskrit and as per the necessity of time, many scriptures and prayers were also composed in other regional languages. As Hinduism is mainly concentrated in India, Nepal, Sri Lanka, Indonesia, and a few other countries, the prayers were composed in the languages spoken in those countries.

Therefore, we can say that Hindus pray in Sanskrit as well as local languages like Hindi, Marathi, Telugu, Tamil, Malayalam, Assamese, Indonesian, Sinhala, Bengali, Nepali, Gujarati, and other Indian languages. There is no restriction on which language to pray in. You can pray in any language.