2nd and 3rd person singular confusion
How do you know when to use third person rather than second person?
Por ejemplo: How are you? is comó está? rather than comó estás. And in section 3.11 Paralee translates pudiera when asking a question in 2nd person, but it's conjugated in 3rd. She's saying: "Can you show me on the map?" It's translated as "Pudiera mostrármelo en el mapa." Why isn't it "Pudieras"?
3 Answers
Like sinsonte sort of said already, one is the formal and one is the informal. When it ends with s, like pudieras, it is tú (informal), and when it ends with no s, like pudiera, it is usted (formal).
Every place has their own rules of which form is prefered for what kind of relationship, but this is a good general rule to follow. It is more polite to speak to people you don't know as usted, and there are plenty of people you may even know very well that also deserve usted, like a teacher, an elder, something like that.
The example you cite in Lesson 3.11 "Hopes and Dreams with the Imperfect Subjunctive" occurs at Timestamp: 13:42.
¿Pudiera mostrármelo en el mapa? is the given example.
This section concerns "polite requests". Paralee does not teach us that polite requests need to be made in the 2nd person. Nor does she provide any example of a polite request being made using the 2nd person.
Here are the two examples given in this section:
(1) Quisiera las alcachofas con gambas. (2) ¿Pudiera mostrármelo en el mapa?
You say "Paralee translates pudiera when asking a question in 2nd person".
Paralee is not using the 2nd person. Both of these statements are made using the formal 3rd person. When Paralee says these two examples, she uses the 3rd person. She doesn't make a pronunciation mistake by including an "s" at the ending of either conjugated verb.
So, my only guess, is that you are thinking that, since it is a polite request, it must be made in the 2nd person. However, that is not what was taught in the lesson, and no examples were given in Paralee's lesson that would lend credence to this idea.
If one wants to be polite, one signals this intention by using the Imperfect Subjunctive. Use of the informal 2nd person doesn't have so much to do with politeness, as it does with other things, such as age of the speakers, age differences, familiarity, relationships, etc.
Use 2nd person when talking to a friend or maybe your children. Use the 3rd person to show respect. Examples include, at work, your grandparents, parents, first meeting someone.
