a year later VS a year on

Question

When one wishes to say that something will happen in the future, one would say, for example, either ten years later or ten years on. What I would like to know is if there are any semantic or stylistic differences between a year later and a year on. Or can they be used interchangeably?

I would also like to know which of the following sounds more natural in English:

1a. Some years later, I did...

1b. Some years on, I did...

2a. It was not until a year or so later that I...

2b. It was not until a year or so on that I...

Answer 1

The primary difference between the examples you used, is that one (later) is less time specific than the other (on).

To say that something happened a year later is generally accepted as being an approximation of the amount of time that has passed. However, the most common usage of "A year on..." is to couple it with a date or event. In addition, ago is often added to that form of usage.

1. A year on Friday marks the anniversary of our meeting.

2. We met a year ago on St. Patrick's Day.

   It is also POSSIBLE to use "A year on..." as a reference to an ongoing situation, but as another person replied, that's a colloquialism and is not frequently seen in common usage.

That said, if you live in an area where on is commonly used in that phraseology, feel free to do so!! English is a forgiving and continually changing language .... Enjoy exploring its panoramic landscape in your journey toward fluency.

Answer 2

In the two examples you give, the one that sounds most natural is later but there are examples which would sound as good using on. For example:

Six years on, this problem still exists.
Six years later, this problem still exists.

They both read okay, however the first one is still a wee bit of a colloquialism.