"Cómo se dice __", meaning "how do you say __", is confusing me.
Why is there
se? Why is dice in él/ella/usted (3rd) form if "cómo se dice" means "how do you say __"? Why isn't it "cómo dices"?
In English, it's possible to ask
How do you say "father"?
How does one say "father"?
These two questions are equivalent, because you has two meanings in English: first, a personal pronoun, as in "Do you want my phone number?" and second, "an unspecified person or people in general", as in "You get tired quicker when it's very hot out" (see http://www.thefreedictionary.com/you).
But in Spanish, tú only has the personal pronoun meaning.
Now, there is a third way you could do it in English, although it's a bit weird:
How is "father" said?
That is the passive voice. And the passive is what is commonly used in Spanish for vocabulary questions. The passive is usually handled in Spanish by making the verb reflexive. Here are some examples of a reflexive verb:
El perro se rasca. (The dog scratches itself.)
Yo me odio. (I hate myself.)
And here are some reflexive verbs that function as passive expressions:
Se contestan las preguntas en la clase. (Questions are answered in class.)
Las calificaciones se anuncian mañana. (Grades are announced tomorrow.)
And that is the construction used in Spanish to talk about vocabulary, for example:
En inglés, "padre" se traduce como "father." (In English, "padre" is translated as "father.")
En español, "papá" se dice más comúnmente que "padre." (In Spanish, "papá" is said more commonly than "father.")
Side note: occasionally, you might hear "Cómo dices 'beans'?" because the exact vocabulary item for "beans" will depend on the country the speaker is from. In one country, the commonly used word will be "frijoles" but in another country it might be something else, such as "habichuelas." So in this case, one person might ask a friend from a different Spanish-speaking country, "How do you, personally, say 'beans'?" ("¿Cómo dices tú 'beans'?")
To express how do you say __?? in Spanish you can use either of your alternatives but in different contexts.
If you want to ask in general how something is pronounced the you will use the se sentence.
¿Cómo se dice chicken en español?
Chicken en español se dice pollo
If you want to ask a person how does he/she say something specific then you ask a personal question.
¿Cómo dices [tú] car en español?
Yo digo carro.
¿y cómo dice car en español alguien de España?
Ellos dicen coche
There is no such a distinction in English because when you ask how do you... you could be asking to a specific [you] person or you could be making a general/impersonal question.
In English, we make a distinction often between you you (the person we're taking to) and you, generally (a non-specific person, that is, how does one say...?). When we ask how do you say...? we more often than not are speaking generally.
Spanish has its own structures to speak generically, and that's what you see here, specifically this is the se impersonal. If we cared specifically about how the person we're speaking with would say a word (as opposed to other people, perhaps), then ¿Cómo. dices...? would be more appropriate
You cannot make a literal translation between English and Spanish.
Cómo se dice - more or less translates to "how is it said".
You are asking a general term - how is it that everyone says chicken?
Whereas if you are asking a personal preference, you can say:
¿Cómo dices? if you are asking me how do I say something.