In my recent post on being immersed in the Samoan language as a missionary I didn't say anything about another important component of my language acquisition: book study.
I'm fairly bookish by nature, so studying from grammars or reading Samoan language materials came naturally.
When we entered the Missionary Training Center, each of us eight missionaries assigned to Samoa received the following language materials:
Samoan for Missionaries, which apparently was a Brigham Young University Master's thesis written by Scott C. Dunn, presumably a former missionary to Samoa (you have to wait a while for the book to load).
G. B. Milner's Samoan Dictionary, an excellent and compact work that I tried to carry with me as much as possible for quick reference.
And the scriptures, or Standard Works, as Mormons call them, including the Bible, Book of Mormon, Doctrine and Covenants, and Pearl of Great Price. (The former for sale here; the latter, as newly revised translations, here.)
When I had been in Samoa for a while, I purchased the Reverend George Pratt's dictionary and grammar (1st, 2nd, and 3rd editions online; I had the 4th), a copy of Gospel Principles in Samoan, and Allardice's Simplified Dictionary of Modern Samoan.
All these works I studied carefully, comparing grammar rules with actual Samoan usage in print and what I heard from day to day until, by the grace of God, I could follow, and contribute to, what was being said all around me.
If you're trying to learn Samoan, don't forget to combine the written and spoken word. That way you'll know what to say and why it's said that way.