Discipula unam sententiam facile legit, sed aliam sententiam intellegere nondum potest.

Discipula is the subject of the sentence, so it is in the nominative singular. It means the female student / schoolgirl / pupil.

A learner may also notice that Latin often does not use the or a/an explicitly. So discipula can mean:

• the student
• a student

The exact English wording depends on context.

Both phrases are direct objects, so both are in the accusative singular.

• unam sententiam = one sentence
• aliam sententiam = another sentence

The adjective must agree with the noun it describes, so:

• unam matches sententiam
• aliam matches sententiam

They all are:

• feminine
• singular
• accusative

That is why you see -am on unam, aliam, and sententiam.

Here sententia means sentence, as in a grammatical sentence.

In other contexts, sententia can also mean things like:

• opinion
• view
• judgment
• thought

But in this sentence, the meaning sentence clearly fits.

Because facile is an adverb, while facilis is an adjective.

• facilis = easy
• facile = easily

Here it describes how she reads, not what kind of thing she is reading. So Latin uses the adverb:

• facile legit = she reads easily

This is similar to English:

• easy = adjective
• easily = adverb

Because it depends on potest.

Latin uses possum (to be able, can) with an infinitive:

• potest legere = she can read
• potest intellegere = she can understand

So:

• nondum potest = is not yet able
• intellegere = to understand

Together:

• intellegere nondum potest = she cannot yet understand

Using intellegit would make it a separate finite verb, which is not what the sentence is doing.

Nondum is a common Latin adverb meaning not yet.

It is built from:

• non = not
• dum = originally related to yet / as yet / while

As a fixed word, nondum simply means not yet.

So:

• nondum potest = she cannot yet / is not yet able

Latin word order is more flexible than English word order. Nondum belongs in sense with potest, but it does not have to stand immediately next to it.

So these all could express basically the same idea:

• nondum intellegere potest
• intellegere nondum potest
• intellegere potest nondum (much less usual in ordinary prose, but possible in some contexts)

The version in your sentence puts some emphasis on intellegere first, then gives nondum potest.

In this sentence, legit is understood as present tense:

• she reads

However, a beginner may notice something important: without macrons, legit can look the same as the perfect form she read.

In more careful marking:

• legit = present, she reads
• lēgit = perfect, she read / has read

Since most beginner texts omit macrons sometimes, context helps. Here the parallel with potest makes the present meaning the natural one:

• She easily reads one sentence, but cannot yet understand another.

Latin could sometimes leave the noun understood, but repeating it is very normal and often clearer.

So:

• unam sententiam ... sed aliam sententiam ...

means very plainly:

• one sentence ... but another sentence ...

Repeating the noun helps the contrast stand out clearly.

Sed means but.

It connects the two clauses and shows a contrast:

• she can do one thing easily
• but she cannot yet do the other thing

So the structure is:

• Discipula unam sententiam facile legit
• sed aliam sententiam intellegere nondum potest

This is a very common Latin way to join contrasting ideas.

Yes. Latin word order is fairly flexible because the endings show the grammatical roles.

For example, you could rearrange the words and still keep the same basic meaning:

• Unam sententiam discipula facile legit, sed aliam sententiam nondum intellegere potest.
• Facile discipula unam sententiam legit, sed aliam sententiam intellegere nondum potest.

That said, word order is not random. Different orders can slightly change:

• emphasis
• flow
• contrast

The given sentence is a natural, clear order.

A good way is to group the sentence by grammar:

• Discipula = subject
• unam sententiam = direct object of legit
• facile = adverb modifying legit
• legit = main verb of the first clause

Then:

• sed = but
• aliam sententiam = object of intellegere
• intellegere = infinitive
• nondum potest = cannot yet / is not yet able

So the two halves are:

• Discipula | unam sententiam | facile | legit
• sed | aliam sententiam | intellegere | nondum potest

That kind of grouping is often the easiest way to read Latin.

Yes. Discipula is the feminine form, so it refers to a female student.

The masculine form would be discipulus.

So:

• discipula = female student
• discipulus = male student

In English, we usually just say student unless we need to show gender.