Article 15 of the Indian Constitution prohibits discrimination by the state on the grounds of religion, race, caste, sex, or place of birth. However, discrimination on the basis of language is not explicitly mentioned in this article and is therefore not prohibited.

Explanation:

- Article 15 of the Constitution is a fundamental right that guarantees every citizen of India the right to equality and prohibits discrimination on certain grounds.
- The grounds on which discrimination is prohibited by the state under Article 15 are religion, race, caste, sex, or place of birth.
- Discrimination on the basis of language is not explicitly mentioned in Article 15, and is thus not prohibited.
- It is important to note that discrimination on the basis of language is prohibited under other provisions of the Constitution, such as Article 29 and Article 30.
- Article 29 prohibits discrimination on the grounds of language, culture, or religion in admission to educational institutions funded by the state or receiving aid from the state.
- Article 30 guarantees the right of minorities to establish and administer educational institutions of their choice, including those based on language.
- Discrimination on the basis of language is also prohibited under various laws, such as the Official Languages Act, 1963, which provides for the use of Hindi and English as official languages of the Union of India and the Eighth Schedule of the Constitution which recognizes 22 languages as official languages of India.

In conclusion, while discrimination on the basis of language is not explicitly prohibited under Article 15 of the Constitution, it is prohibited under other provisions of the Constitution and various laws.