1. Three important rules that govern the way elements combine to spell words are the Rule of Simple Addition, the Twinning Rule, and the Final <e> Deletion Rule. A fourth important rule governs the changes that occur in the final consonants of some prefixes when they are added to certain stems. The consonants change their sound and spelling to be more like, or similar to, the first sound and letter in the stem. When sounds and letters change this way to be more similar to a sound or letter near them, the process is called assimilation.
For instance, the word assimilate actually contains an assimilated spelling of the prefix ad-: ad + similate = ad+ s + similate = assimilate. The sound [d] and the letter <d> in ad- change to [s] and <s> to be more similar to - or in this case, exactly the same as -the first sound and letter in the stem similate.
2. All of the following words start with some form of the prefix ad-. Sometimes the prefix assimilated when it combined with the stem; sometimes it combined by simple addition. Analyze each word into its prefix and stem. Be sure that your analysis shows any assimilation that took place when the prefix and stem combined.
Prefix + Stem
3. Other prefixes that often assimilate the way ad- does are sub-, in-, ob-, com-, and ex-. Each one of the following words starts with one of these five prefixes. Sometimes they have assimilated, and sometimes they have combined by simple addition. Analyze each word into its prefix and stem. Be sure that your analysis shows any assimilation that has taken place:
Prefix + Stem
4. When the last consonant in a prefix changes its sound and spelling to be more similar to the sound and spelling at the beginning of the stem, the process is called ________.