Q. A person who has a hard time davening in Hebrew (it takes a long time to do so, he is just starting to learn how to daven in Hebrew), may he recite part of the SE (e.g., 1st three and last three brachos) in Hebrew, and the middle brachos in English (or is it considered disrespectful to mix languages in one SE, as one would not speak that way in front of a king)?
When davening in English, may one pronounce the Eibeshter’s name (Ad-noy) as Lord and Elokeinu as G-d, or is this invalid and requires that one repeat the tefilla?

A. Mishna Berura (62: 3) rules that one may recite the amida in any language that he understand, but it is preferable to say it in Hebrew.
Horav Shlomo Miller’s Shlit”a opinion is that one may divide if necessary the amida and recite parts of it in another language.
He also maintains that the names of Hashem should be said in Hebrew, even if the rest is recited in another language.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a