Audio balancing and levels

I noticed that some pronunciations, such as for "ri" are very quiet compared to other pronunciations. Also, for the more audible pronunciations, it's still a bit quiet and have to put my volume to almost 3/4 max to be able to hear most of them. Would it be possible to balance the audio so they're all the same volume, and make them all louder so they're more audible at lower volumes?