How to use だんだん properly?


If I wanted to say, "Ken's getting better and better at Japanese", then would
this be correct?

> けんさんはだんだんじょうずになります。




Your usage of だんだん is just fine. It's a standalone adverb which can be used
without any other particle. An adverb is usually placed just before what it
modifies (in this case, じょうずになる).

* * *

You have to use the progressive form of なります; otherwise the sentence would
mean "Ken gets (or will get) better and better at Japanese".

> けんさんはだんだん日本語【にほんご】が上手【じょうず】になっています。

To make this a bit more natural, you can add a subsidiary verb
[～てくる](https://japanese.stackexchange.com/q/676/5010) and say:

> けんさんはだんだん日本語が上手になってきています。




Your usage of だんだん is just fine. It's a standalone adverb which can be used
without any other particle. An adverb is usually placed just before what it
modifies (in this case, じょうずになる).

* * *

You have to use the progressive form of なります; otherwise the sentence would
mean "Ken gets (or will get) better and better at Japanese".

> けんさんはだんだん日本語【にほんご】が上手【じょうず】になっています。

To make this a bit more natural, you can add a subsidiary verb
[～てくる](https://japanese.stackexchange.com/q/676/5010) and say:

> けんさんはだんだん日本語が上手になってきています。

