you can say -> han-guk-er-reul jal-ha-gi-wii-hae ee-gur-juk-er-yo 한국어를 잘하기위해 이걸적어요. also you can use google-trans for hearing this sentece, i am sure, you can hear perfect pronounce. best luck

Not on topic, but should it not be: can I get some help with this translation please? Hence using the preposition 'with' instead of 'on'? This 'on' just sounds strange to me.

I am not Korean, but I am learning the language, so I thought I'd give this a try. There are a number of different verbs to mean "improve". Here's my best translation: 제 한국어 진보하기 위해서 이거 쓰고 있어요