High is a hard-working word: it's an adjective, a noun and an adverb. It also ends in 'gh', like laugh or neigh. Have you ever wondered where that 'gh' came from. Feels like an appendix, doesn't it - like, you have one, but you don't really need it, but maybe it served some vital purpose way in the past. Well, the 'gh' at the end of an English word actually used to be pronounced! The sound it makes (called a voiceless velar fricative for anyone needing some trivia to torture a younger sibling with) is like a cross between a 'ka' and a 'ha'. It is a sound used in Gaelic, whence many of our modern English words derive. 

Of course, it's not pronounced now, so if you add a voiceless velar fricative to end of a word meaning 'of great vertical extent', be prepared for someone to turn to you and say, "Gesundheit!"