Why do some mutations change the protein that is produced, but other mutations do not?

DNA can’t leave the nucleus and need to get the information into the cytoplasm using mRNA. If DNA replication made a mistake and changes the codon and anticodon the word changes, and it changes the protein. Usually changes the structure as well. If the mutation is in the base pair it could be the same, there are more words then there are amino acids because anything that starts with the first two letters determines what is formed. That is a silent mutation. Matters where the mutation is and what kind of mutation it is.