Our son, Quinn, who is a sophomore at Stanford University majoring in math and computational science, has just had his Chinese-English Dictionary application approved by Apple.

He created it for people who are learning Mandarin, but tells me it could potentially be useful to a curious traveler to China or Taiwan who doesn’t speak the language.

Called “ChineseDict,” it has three features that other iPhone dictionaries don’t have:

1. Fast as-you-type searching.

2. A good word frequency list, so that more relevant words appear first (searching for “Beijing” gets you the entry on the capital city, as you’d expect, not the entry on “Beijing Geology University”).

3. An iPhone-like look and feel, which all apps don’t have. Apparently, it takes quite a bit of effort to make iPhone apps feel like iPhone apps.

When he launched ChinesDict, it had just 12,000 words. An updated version lets you search 80,000 words.

So far he’s had 60 purchases (@ $3.99, although he’s taking the price on the updated version down to $2.99), with 12 yesterday and the number going up by about two each day. He expects the new version, once live, to be much more successful.

A free notepad app, QuickNote, has already seen 500 downloads as of yesterday.