This is NOT stackable with the Windows Phone version.
In Alphajax, there are two tiles worth 10 points; Q & Z. If you have a Q or Z, the two letter words you want to look out for are QI and ZA.
There are tiles with 'TL' scattered around the board. Put the Q or Z on it as an official word, and you'll get the achievement.
Oddly, the word ZO is not an official word in Alphajax, and ZA is.