"Somnia" is not a word; "insomnia" is. That's just English. Non-native speakers (like me) beware. There are as many exceptions to the rules as those that follow the rules. Not only many words starting with "in" don't have corresponding antonyms that lose the prefix "in", but also some "in" and non-"in" pairs completely disregard the … Continue reading Insomnia vs. Somnia →