But in Google IME, that isn’t needed. In ‘Dictionary’ tab, you can edit your own dictionary, or import/export a custom dictionary file.
Also, Google IME seems to have auto-generated dictionaries from the search engine database, so, so many 顔文字’s. This is one of the features Google advertised.
I might (or might not) look for the way to change the interface language later. I can live with the existing problem for the time being, while I aim for the better understanding of Japanese.
In case anyone else runs into this, user dictionary words do not show up in the ‘tab’ menu. There’s actually another way to select kanji with the Google IME, which is to hit the space bar. The space bar menu will include items from the user dictionary.