Learn Hardcore Spanish (Spain): Mi hermana está orgullosa de mí porque ya no tengo tanta vergüenza. - My sister is proud of me because I am not so embarrassed anymore.

The noun is hermana (sister), which is feminine singular.
Therefore, the adjective must also be feminine singular: orgullosa.
If it were mi hermano (my brother), you would say:
- Mi hermano está orgulloso de mí.

So:

Mi hermana está orgullosa… (feminine)
Mi hermano está orgulloso… (masculine)

What’s the difference between estar orgulloso/a and ser orgulloso/a?

They are quite different:

Estar orgulloso/a (de) = to be proud (of something/someone), usually in a positive, situational sense.
- Mi hermana está orgullosa de mí.
  My sister is proud of me (because of what I did / how I’ve changed).
Ser orgulloso/a = to be proud in the sense of being arrogant, conceited, stubbornly prideful. This is usually negative.
- Es muy orgulloso; nunca admite que se equivoca.
  He’s very proud; he never admits he’s wrong.

In this sentence, we clearly want the “she feels proud of me” meaning, so estar orgullosa de mí is correct.

Why is it de mí and not de yo?

After most prepositions in Spanish (like de, para, con, por), you must use the stressed pronouns, not the subject pronouns.

Subject pronouns: yo, tú, él, nosotros, vosotros, ellos…
Stressed (prepositional) pronouns: mí, ti, él, nosotros, vosotros, ellos…

So you say:

orgullosa de mí (proud of me), not de yo
para mí (for me), sin mí (without me)

Examples:

Está hablando de mí. – He/She is talking about me.
No confía en mí. – He/She doesn’t trust me.

What exactly does ya no mean here, and why is the order ya no instead of no ya?

Ya no together means “no longer” or “not … anymore.”

ya = already / now
no = not
But when combined as ya no, the fixed phrase means:
ya no tengo tanta vergüenza = I no longer feel so much embarrassment / I’m not so shy anymore.

The normal order is ya no, not no ya.
No ya is not used in modern Spanish with this meaning.

You can move ya no a bit in the sentence, but it still stays together:

Ya no tengo tanta vergüenza.
No tengo ya tanta vergüenza. (possible, but less common in everyday speech)

The important thing: ya must go with no to create “no longer.”

Why is it tanta vergüenza and not mucho vergüenza, muy vergüenza, or tan vergüenza?

Vergüenza is a feminine, uncountable noun here (embarrassment/shyness), so you need a quantifier that fits a feminine noun.

tanto/tanta/tantos/tantas = so much / so many
Feminine singular: tanta → tanta vergüenza

Other options:

mucho vergüenza → wrong, because mucho must agree:
- mucha vergüenza = a lot of embarrassment (this one is correct Spanish, but means “a lot of embarrassment,” not “so much/the same as before”).
muy goes with adjectives or adverbs, not directly with nouns:
- You can’t say muy vergüenza.
- But you can say muy avergonzado (very embarrassed).
tan also goes with adjectives/adverbs, or with mucho/mucha:
- tan vergüenza → incorrect
- tanta vergüenza → correct
- tan avergonzado = so embarrassed

So tanta vergüenza = so much embarrassment / shyness.

Why is it tengo vergüenza and not estoy avergonzado or soy tímido?

Spanish expresses some feelings or physical/mental states with tener + noun, not estar + adjective.

tener vergüenza = to feel embarrassed / shy / self-conscious
estar avergonzado/a = to be embarrassed (more focused on a specific incident)
ser tímido/a = to be shy as a general personality trait

Nuances:

Ya no tengo tanta vergüenza.
= I’m not as shy / embarrassed as before (my general level has decreased).
Ya no estoy tan avergonzado.
= I’m not as embarrassed now (probably about a particular event).
Ya no soy tan tímido.
= I’m no longer so shy as a person (more about character).

The original sentence focuses on the amount of shame/embarrassment as a feeling, so tengo tanta vergüenza is perfect.

Could I say Mi hermana se siente orgullosa de mí instead of está orgullosa de mí?

Yes, that’s possible, and it’s natural Spanish. Both are correct but with a slight nuance:

Mi hermana está orgullosa de mí.
Focuses on her state: she is in a proud state because of something you did.
Mi hermana se siente orgullosa de mí.
Focuses more explicitly on her emotion/feeling: she feels proud of you.

In many contexts they’re interchangeable. Using se siente just highlights the emotional aspect a bit more, but it doesn’t change the meaning much.

Why is the tense está / tengo (present), not something like a progressive form?

In Spanish, the simple present is used much more often than in English to talk about:

current states and feelings
habits and general truths

So:

Mi hermana está orgullosa de mí.
= My sister is proud of me (now / these days).
Ya no tengo tanta vergüenza.
= I don’t have so much embarrassment anymore / I’m not as shy anymore.

You generally don’t say:

Mi hermana está estando orgullosa de mí. (incorrect)
Estoy teniendo vergüenza. (incorrect in normal Spanish)

The progressive (estar + gerundio) is reserved for actions in progress, not for most states (being proud, having shame, etc.).

Why is it porque and not por qué or just por?

Spanish distinguishes:

porque (one word, no accent) = because, introducing a reason.
- Mi hermana está orgullosa de mí porque ya no tengo tanta vergüenza.
  My sister is proud of me because I’m not so shy anymore.
por qué (two words, with accent) = why, used in questions.
- ¿Por qué está orgullosa de ti tu hermana?
  Why is your sister proud of you?
por alone = because of / due to / for, usually followed by a noun, pronoun or verb in the infinitive:
- Está orgullosa por mis progresos.
  She’s proud because of my progress.

Here, we’re introducing a full subordinate clause (ya no tengo tanta vergüenza), so we use porque = because.

How is vergüenza pronounced, and what’s the function of the ü?

Vergüenza is pronounced approximately: [ber-GWEN-tha] in most of Spain (with the th of think), and [ber-GWEN-sa] in Latin America and some parts of southern Spain.

The ü shows that the u must be pronounced in the -güe- / -güi- combinations.

Without the diaeresis (¨):
- gue / gui → the u is silent:
  - guerra = [ge-rra]
  - guitarra = [gi-ta-rra]
With güe / güi:
- The u is pronounced:
  - vergüenza = [ber-gwen-tha] / [ber-gwen-sa]
  - pingüino = [pin-gwi-no]

So the ü tells you: “Pronounce this u as w.”