Although I dont completely agree, many consider "Q", "X" and "Z" to be the primary letters that are weak. (Barring obvious combos like "XXX", "IQ", or a shorthand abbrev like "PLZ".) The reasoning is that there are far less potential acronyms w/ these letters than w/ most others. However, that just takes English into acct. "X", "Z", and, (to a lesser extent), "Q" are used frequently and associated w/ sounds in Pinyin Chinese, and other derivations that translate Asian languages into a western alphabet . Several product IDs use "X"- XP, XL, etc, and X can substitute for words such as extreme and extra, ie XXL or the sound "icks" as in "kix
