You've familiar with prefixes and suffixes, but a lesser-known "affix" is the infix, which involves the insertion of a sound into the middle of a word. These show up pretty rarely in English, but back in Proto-Indo-European, the sound -ne- was pretty frequently inserted before the last consonant of roots to create a present active verb. This was called a nasal infix, and it mostly passed into Latin, Lithuanian, Ancient Greek, Sanskrit, and various Slavic languages. You can see some great examples of this phenomenon in pairs of Latin-derived words:
Hello! I'm Adam Aleksic. This year, I graduated from Harvard University with a degree in Government and Linguistics. There, I co-founded the Harvard Undergraduate Linguistics Society and wrote a thesis on Serbo-Croatian language policy, magna cum laude. In addition to etymology, I also really enjoy philosophy, trivia, vexillology, geography, board games, conlanging, art history, and law.