How to edit some words of a file subtitle and place them in the center of the screen

Is there a software that allows me to edit only some words(colour, size, etc) of file subtitles and place them big in the center of the screen?, kind of like it is made with lyrics of a song on youtube.

Subtitle workshop has options like colour, bold, but not size and placement on the screen, if it has them, where are they? I'm not an expert.

I also try aegisub, whilst it does allows me the placement on the screen, the editing options of the words are so confuse that i dont know if it's posible to change colour of two word in the same line for example.

Thanks.