Why is there a U in 'guess', 'guitar', and 'guard' if you never hear it? The U looks useless, but it does a specific job in English spelling. Once you know that job, these words stop being confusing.
The Rule
The letter G is 'soft' (/dʒ/, like J) before E, I, and Y, as in 'gem' and 'giant'. To keep G hard (/ɡ/) before those letters, English inserts a silent U. So 'guess' is /ɡɛs/ (not 'jess'), and 'guide' is /ɡaɪd/ (not 'jide'). The U is a spelling signal, not a sound.
The U is silent here
When the U Is Actually Pronounced
In a smaller group of words, the U in 'gu' is not silent: it is pronounced /w/, so 'gu' sounds like /ɡw/. This usually happens when the U comes before A or another vowel that is fully sounded.
Exceptions to Watch
A few words break the neat pattern. 'Argue' ends in /ˈɑːrɡjuː/ with a clear U sound. 'Guarantee' keeps the silent U (/ˌɡærənˈtiː/), while 'penguin' sounds the U. When in doubt, remember the core idea: a silent U almost always exists to protect a hard /ɡ/.
Practice Tip
Group the words: silent-U words (guess, guest, guide, guilt, guitar, guard) versus sounded-U words (language, penguin, anguish). For more on hard and soft G, read our guide to the hard and soft G rule.