Apple Spellcheck keep mis-spelling words on my iPad and how can I fix it?

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• Re Spelling. Apple iPad user here with up to date Word. Can anyone please tell me the likely reason why I continually have certain words being mis-spelt requiring significant time to physically correct the mistakes?. I’m also seeking a simple step- by-step analysis of how the mechanics of this process actually works? When am error happens (e.g. artartbecomes like this) of I tap the error I’m presented with the solution which than corrects the word. I’m a bit gobsmacked that it’s doing this and refuse to believe that of we can put a man on the moon we CAN'T SEEM TO FIX THIS VERY BASIC BUT CATASTROPHICALLY ANNOYING FAULT IN THE PROGRAMME!!?

[Re-Titled by Moderator]

Original Title: Fault with Apple Spellcheck