Once you know how to spell it, you have it. One can hear a word hundreds of times, even know its meaning, but unless you can spell each syllable, you may not remember, or use it. At least that’s my experience. I tend to avoid using a word that is spoken, but not written. Written, it stays with me; otherwise, it remains a bit fuzzy in the mind and doesn’t clearly register. Seeing the word spelled, divided into syllables, one makes connections and recognizes derivations. Then it can become part of one’s vocabulary.