What can be discerned about the speaker in the poem "Bilingual/Bilingue" by Rhina H. Espaillat, drawing only on what the poem tells you or reveals?

This question proposes an interesting exercise, as the speaker of a poem is not always necessarily the same as the author of a poem. 

Character’s Age and Situation in Life

First, the speaker is clearly female, as she refers to herself as her “father’s daughter.” It can be assumed that she was born into a family that has recently (within a few generations of speaker) immigrated to an English-speaking country, as there is still a clear division between the language spoken at home (Spanish) and outside the home in society (English). Considering that she is living in her father’s house under his rules, we can also assume that she’s young, at least young enough to still be living with her parents.

Attitude toward Self and Others/General Personality

The speaker’s father is afraid that his legacy and heritage would be lost to her, but she feels at ease in both worlds (though he was afraid her heart would be divided, she notes that it remained “one” as she “hoarded secret syllables”). This shows something of a rebellious nature against her father’s wishes and a willingness to assimilate that she did not inherit from him. She clearly has a need to express herself in her own identity and not the identity her father expresses; by the end of the poem, she’s defied her father, signaled by the Spanish text appearing naturally in her speech, without the parentheses used to call out the Spanish in earlier stanzas.