What is the best way to invite non-Arabic speakers to Allah: Should it be by inviting according to personal knowledge, or by utilizing books and letting them read them, and can assistance be provided by offering specific books for this purpose?

Striving to guide people is one of the greatest acts of worship. It is not a condition for da'wah (inviting to Islam) that a person be knowledgeable of everything; rather, one should invite with what they know.

You can invite foreigners and others with what you have learned from the true religion, and avoid what you do not know.

You can seek help from beneficial books and from translated materials available on Islamic websites.