Input Language Changes (apparently) Randomly


I use several languages for input in Mac OS 10.3 (Spanish, English, and Hiragana and Katakana and Romaji for Japanese). Fairly recently, the input will change, apparently randomly. This happens very frequently now, even though my OS default language is set to English and nearly all of my documents are in English. Oddly, it happens even if I don't have any sort of text document open. I can't get it to reliably repeat this behaviour with any sort of action, though it happens several times in the course of a half-hour.

Thank you very much for the assistance!
Ryan Miglavs