What is the difference between She smiled at him. and She smiled to him.? Sometimes, there is none. Other times, one might clearly be correct (or incorrect). It’s useful to look at individual examples of preposition use like this with examples and explanations to get a grasp of them in practice, as I have previously covered with topics such as display with in and on, or by/on foot. So what can the difference between smile to and smile at tell us?

• She smiled at him. – the smile was caused by him, a smile towards him because it is a smile created because of him.
• She smiled to him. – the smile is communicative, sent in his direction; a smile towards him because it is one to be seen, to be shared with him.

As a smile is normally spoken of when something causes it, smile at is much more common and considered the more correct form in general. Though in many situations you may find the two used interchangeably, simply because a smile caused by something is usually also directed at it. But to smile to something will have its uses too. With different objects this can become clearer, and the uses more distinct.

• She smiled at his funny behaviour.
• She smiled to him so he would know she cared.

In these examples, to smile at is more like smile because of… while smile to is like smile for… Consider:

• She smiled at the joke. – the joke made her smile
• She smiled to the guard as they walked past. – the smile was specifically used to share a communication

These are not absolutes, and people may argue them one way or another. But hopefully this goes some way to explaining how different preposition uses with similar meanings can sometimes lead to different points.