Hello, newbie here

Ive had this problem for ages, when Im passing the spelling and grammar checker I tend to misspell the same words in the same way. Now, the checker doesnt suggest any of the correct words for my misspellings. Example

(spanish)

I type "d ela" when what I want is "de la" but the suggestion box at the right never suggests "de la", how can I add as a suggestion "de la", and how can I add similar cases for misspellings when the right word isnt in the suggested box, so next time the checker encounters that word, suggests exactly what I want?

Not sure if I made myself completely clear, let me know if I have to explain further