The Past Tense has many Allomorphs in English.
But suppose I jog today. Yesterday I jogged. Here the bound morpheme is pronounced /d/, although it is spelled "ed." So now we have two allomorphs again for past tense--/t/ and /d/.
And what if I land softly today. Yesterday I landed softly. Note that it is spelled "ed," but pronounced /did/. And then there is "rise" and "risen," and "run" and "ran," and more.
Learning this is not a task for babies, or is it?
3. Male/Female: In some languages, bound morphemes are used extensively to indicate Gender. Was I shocked, for example, in my Russian 100 class to find out that all Russian nouns have Gender.
And its not just a choice of two but three: masculine, feminine and neuter. There is a bound morpheme for each.
There are some gender endings in English, although its a paltry number when compared to Russian.