Today we’re looking at till (or more properly, ’til, although the Oxford Dictionaries no longer include a listing for ’til) and until, which I do see being used interchangeably by both native and non-native English speakers (this is quite rare, actually: most of the pairs I’ve been talking about are usually only found in native English speakers, in my experience. Non-native English speakers have all sorts of other common issues, but not these.) (That gives me an idea for a new series of posts!).
Anyway: till and until. I have consulted the dictionaries and reference books and … they are the same. They mean up to a particular point in time or an event that is being mentioned (“He wasn’t able to take any holiday days until Christmas”), but in a sense that’s more concentrated on that particular date or event, as opposed to a word such as by which is more about the period itself. (“He was told to take all of his holiday by Christmas but he didn’t manage to do it until the gap between Christmas Day and New Year’s Eve”; “You can’t play on the Playstation until you’ve finished your homework”).
Until is considered to be more formal, occurring more often in written English. Till is, wouldn’t you know it, more informal, and occurs more in spoken English. Till is also used as a noun (a cash register or a glacial deposit) or a somewhat archaic agricultural verb to do with preparing the soil before planting a crop.
However, there is one important distinction: you always use until when starting a sentence.
“She gave him the pills till he felt better” or “She gave him the pills until he felt better” but always: “Until he felt better, she continued to give him the pills”.