Words can also be made up of more than one morpheme. English speakers know that one can add the plural(more than one) morpheme, "-s," to the end of "dog," and create the word "dogs". The new word combines the meanings of the two morphemes, so the meaning of the new word, "dogs" is "more than one dog." "Dog" is a free morpheme, but the plural morpheme "-s" is not. It must attach to a word (no native English speaker would use "-s" as a stand alone word). Morphemes which must be attached to a word are called "bound morphemes". Morphemes attached to the front of a word are called "prefixes". Those attached to the end are called "suffixes". Some morphemes can attach in the middle of a word and are called "infixes". (example?)