Here is a technique for the representation of foreign speech chosen by Hemingway in For Whom the Bell Tolls.  Not often imitated, it is notable for its unconventional and mixed methodologies including 1) Archaisms,  2) Anglicization or direct translation of idiomatic elements,  3) Italicized foreign words.

Here’s an example:

As they came up, still deep in the shadows of the pines, after dropping down from the high meadow into the wooden valley and climbing up it on a trail that paralleled the stream and then left it to gain, steeply, the top of a rim-rock formation formation, a man with a carbine stepped out from behind a tree.