You might think it comes from European languages and/or customs, but I think it has its root in halacha.
The standing certainly has its source in the Babylonian Talmud, Makkot 22b (for any Hebrew learners who are reading this, this is in Aramaic, so don't be confused by it):
אמר רבא כמה טפשאי שאר אינשי דקיימי מקמי ספר תורה ולא קיימי מקמי גברא רבה
Rava says, How stupid are other people who stand in front of a sefer torah, and do not stand in front of a great man.
From this, we derive the halachot of standing before a תלמיד חכם and other classes of important people.
As far as addressing rabbis in the third person, I believe the source for this is the prohibition of mentioning one's father or rabbi by name, also found in the Babylonian Talmud in a passage discussing the commandment of honoring one's father and mother, Kiddushin 31b (this time in Hebrew, except for the two introductory words, because it's a beraita):
תנו רבנן חכם משנה שם אביו ושם רבו תורגמן אינו משנה לא שם אביו ולא שם רבו
Our sages taught [in a beraita]: A sage [when speaking] changes his father's name and his rabbi's name [i.e. replaces the name with another word, such as "my father" or "my rabbi"], but an interpreter does not change neither his father's name nor his rabbi's name.
This is the source for the halacha that one may not refer to one's father or one's rabbi directly by their name. Even though the Beraita speaks only of a sage and an interpreter, really what's it's doing is giving special cases for a law that one is presumed to already know, and thus it is saying that this applies even to a sage, but not to an interpreter (since he is just repeating the words of the one he is interpreting for).
Though I do believe that the extension of this to always referring to a rabbi/teacher in the third person happened later, and possibly only in Ashkenazi lands, but I have not looked into this.