Learn Hardcore Romanian: Sora mea învață singură la bibliotecă, dar este la fel de rapidă ca noi. - My sister studies alone at the library, but she is as fast as we are.

Also note that soră (indefinite) becomes sora (definite – “the sister”) when you add a possessive, so sora mea is literally the sister mine, used to mean my sister.

Putting mea before the noun is only possible in a few set expressions or for strong emphasis, e.g.:

draga mea soră = my dear sister
scumpa mea = my dear (fem.)

But Mea sora on its own is not correct.

What exactly is învață? Is it “learns” or “studies”?

Învață is the 3rd person singular present of the verb a învăța.

a învăța = to learn / to study (and, in some structures, to teach)
(ea) învață = she learns / she studies

Romanian has only one present tense, so învață can mean both:

She learns
She is learning / is studying

Context tells you whether it feels more like “learns” or “is studying” in English. In this sentence, the idea is “My sister is studying by herself at the library.”

Why is it singură and not singur?

Singur / singură / singuri / singure must agree in gender and number with the noun:

masculine singular: singur
feminine singular: singură
masculine plural: singuri
feminine plural: singure

Because sora is feminine singular, you must use singură:

Sora mea învață singură = My sister studies by herself / alone.
Fratele meu învață singur = My brother studies by himself.

So singur would be correct for a masculine subject, but with sora you need singură.

Does singură mean “physically alone” or “without help”?

It can mean either, depending on context:

Physically alone
- No one else is there:
  Sora mea învață singură la bibliotecă.
  She studies alone at the library (no one with her).
Without help / on her own
- She gets no help, does it independently:
  Și-a făcut tema singură. = She did her homework by herself.

Often, both ideas are implied at the same time. You can reinforce the “without help” meaning with:

de una singură
Sora mea învață de una singură la bibliotecă.
pe cont propriu (more idiomatic)
Învață pe cont propriu. = She studies on her own.

Why is it la bibliotecă and not în bibliotecă?

Both are possible, but there is a nuance:

la bibliotecă = at the library (as an institution / usual place)
Neutral, very common for places like school, work, the library:
- la școală (at school)
- la birou (at the office)
- la bibliotecă (at the library)
în bibliotecă = in(side) the library
Focuses more on being physically inside the building:
- Sunt în bibliotecă. = I am in the library (inside).

In your sentence, la bibliotecă sounds more natural because it talks about where she goes to study, not just her physical location at this moment.

Why is there no article like o or -a with bibliotecă?

Romanian has:

o bibliotecă = a library (indefinite singular)
biblioteca = the library (definite singular)

But with la + place, when you mean a typical institution or place, Romanian often uses the bare noun (no visible article):

la școală (at school) – not usually la școala
la muncă (at work)
la bibliotecă (at the library)

So la bibliotecă is the natural expression for “at the library” in general.
You can say la biblioteca to strongly refer to a very specific library already known from context, but the common, neutral form is la bibliotecă.

How does the structure la fel de rapidă ca noi work? Is it the same as “as fast as us”?

Yes. La fel de ... ca ... is the standard way to say “as ... as ...”.

Structure:

la fel de + adjective/adverb + ca + noun/pronoun

Examples:

Este la fel de înalt ca mine.
He is as tall as me.
Aleargă la fel de repede ca tine.
She runs as fast as you.
Este la fel de rapidă ca noi.
She is as fast as us.

You must keep the de; you can’t say la fel rapidă ca noi – it has to be la fel de rapidă ca noi.

Why is it rapidă here and not repede?

Because in the sentence we have:

(sora mea) este la fel de rapidă ca noi

Here rapidă is an adjective describing sora (She is fast). It agrees in gender and number:

masculine singular: rapid
feminine singular: rapidă
masculine plural: rapizi
feminine plural: rapide

If you wanted to describe how she studies (the manner of the action), you’d use an adverb, typically repede:

Sora mea învață la fel de repede ca noi.
My sister studies as quickly as we do.

Both are correct, but:

este la fel de rapidă = she (as a person) is as fast as we are
învață la fel de repede = she studies as quickly as we do

Why is it ca noi and not ca pe noi or ca și noi?

After ca in comparisons, you use nominative pronouns, without pe:

ca mine, ca tine, ca el, ca ea, ca noi, ca voi, ca ei, ca ele

So:

la fel de rapidă ca noi = as fast as we are / as fast as us

Using pe (accusative marker) is wrong here:
✗ la fel de rapidă ca pe noi

About ca și noi:

Many speakers say ca și noi in everyday language.
However, in standard grammar this is considered unnecessary or hypercorrect in simple comparisons.
Recommended in careful/standard Romanian: la fel de rapidă ca noi.

So the safest, most correct form in writing is ca noi.

Can we change the position of singură? For example: Sora mea învață la bibliotecă singură?

Yes, you can move singură, but it slightly changes the emphasis:

Sora mea învață singură la bibliotecă.
Neutral: she studies alone at the library. (focus on the fact she studies alone)
Sora mea învață la bibliotecă singură.
Still correct; the focus shifts a bit towards the place (at the library) and then adds that she is alone there.

What sounds unnatural in normal speech is:

✗ Sora mea singură învață la bibliotecă.

Without commas, that sounds odd. With commas, it becomes a different structure:

Sora mea, singură, învață la bibliotecă.
My sister, alone, studies at the library. (adds “alone” as extra information)

The most neutral and common for this meaning is the original order:
Sora mea învață singură la bibliotecă.

What does dar do here? Could we use însă or ci instead?

Dar is a common conjunction meaning but / however. It introduces a contrast:

… învață singură la bibliotecă, dar este la fel de rapidă ca noi.
… she studies alone at the library, but she is just as fast as us.

Alternatives:

însă – very similar to dar, a bit more formal or “written style”:
…, însă este la fel de rapidă ca noi.
ci – this is different: it’s used only after a negation to correct or oppose something:
- Nu învață acasă, ci la bibliotecă.
  She doesn’t study at home, but at the library.

In your sentence there is no negation, so you must use dar (or însă), not ci.

Why does Romanian use the simple present here? Would învață be “studies” or “is studying”?

Romanian has only one present tense, which covers both English:

simple present (“studies”)
present continuous (“is studying”)

So Sora mea învață singură la bibliotecă can mean:

My sister studies alone at the library. (habit)
My sister is studying alone at the library. (right now)

Context decides which English form sounds better. Grammatically, învață is just present tense, without a separate continuous form.

How do you pronounce the special letters in învață, singură, bibliotecă, rapidă?

Key Romanian diacritics in this sentence:

î in învață
- Sound: a central vowel, like French u in tu, but shorter; not like English ee.
- Approx.: say a very closed uh.
ă in învață, bibliotecă, rapidă
- Sound: a short, neutral vowel (schwa), like a in about.
- învață ≈ în-vă-tsă
- bibliotecă ≈ biblio-te-kă
- rapidă ≈ ra-pi-də
ț in învață
- Sound: ts as in cats.

Together, a rough pronunciation guide:

Sora mea învață singură la bibliotecă, dar este la fel de rapidă ca noi.
≈ Sora mea în-vă-tsă singură la biblio-te-kă, dar este la fel de ra-pi-də ca noi.