Explanation:

- Article 343(1): This article states that Hindi in Devanagari script shall be the official language of the Union. It lays the foundation for the language policy of the central government.

- Article 343(2): This article deals with the continued use of English for official purposes within the Indian Union for a designated period, which was initially set as fifteen years from the commencement of the constitution.

- Article 343(3): This part allows Parliament to legislate for the use of English beyond the fifteen-year period.

- Article 354(2): This article is not related to the official language. It pertains to financial emergency provisions in the constitution.