I consider myself competent in both English and the document’s original language. Will the IRS accept my translation of a document?
What? What are you trying to do?
I am a multi-national U.S. taxpayer. Some of the tax records are written in a foreign language. Must a U.S. taxpayer spend a large amount of time and money translating the documents into English for the IRS? The IRS, whose requirements at https://www.irs.gov/pub/irs-pdf/iw7.pdf does not specify what constitutes a “certified translation”.
Well now that you have been more specific in which "docs" you are talking about ... the W-7 instructions page 3 says :
3. The documentation you provide must be current (that is, not expired).
There are 13 acceptable documents, as shown in the following table. At least one document must contain your photograph, unless you’re a dependent under age 14 (under age 18 if a student). You may later be required by the IRS to provide a certified translation of foreign-language documents.
So if that is needed you can ask the IRS about how to get it. The IRS has translators on the payroll so unless this is written in Martian you should not have an issue.