To solve this problem, Korean uses this letter: . When it starts a syllable, it is a silent placeholder consonant.
This lets us write o-hu as: . The first syllable now begins with a consonant that doesn't get pronounced.
Here are some other Korean words that use the placeholder:
, meaning inside and pronounced an (that's the ah sound for the vowel, remember?)
, meaning "right" (as in right-hand) and pronounced u (that's the u sound in June).
, meaning "grace, suavity," and , meaning "peace" or "well-being."