You can put diacritics over an arbitrarily large base by using an accent object in a math zone. For example, in my email editor (Outlook), I type alt+= to insert a math zone and then (a+b)\tilde<space><space> to get
[cid:image001.png@01CB80BE.389DD340] (wide tilde over a+b). Evidently linguistic analysis yet another field in which mathematical typography is useful. Murray
<<inline: image001.png>>
