Where does “লাৎভিয়া” come from?

লাৎভিয়া (Assamese) comes from English Latvia, from Latvian Latvija, from Latvian latvis, from Latvian latuvis, from Latvian Latuva.

Ancestry of “লাৎভিয়া”, step by step

Step	Language	Word	Meaning
1	English	Latvia	—
2	Latvian	Latvija	Latvia
3	Latvian	latvis	a Latvian, a Lett; a member of the Latvian...
4	Latvian	latuvis	—
5	Latvian	Latuva	—