Magistra dicit artem bene scribendi usu paulatim crescere.

Because after dicit (says), Latin often uses an indirect statement construction:

• verb of saying/thinking/perceiving
• • accusative subject
• • infinitive verb

So in Magistra dicit artem ... crescere, the word artem is the subject of crescere, but in an indirect statement the subject goes into the accusative, not the nominative.

So:

• direct idea: ars ... crescit = the art/skill grows
• reported after dicit: artem ... crescere = that the art/skill grows

For the same reason: this is an indirect statement.

After verbs like dicit, Latin usually does not use a separate word for that plus a finite verb. Instead it uses:

• accusative + infinitive

So:

• English: The teacher says that the skill increases
• Latin: Magistra dicit artem crescere

Here crescere is the infinitive meaning to grow / to increase, but in this construction it functions as the verb of the reported statement.

Because Latin normally does not need one here.

English says:

• The teacher says that ...

Latin usually says:

• The teacher says [accusative + infinitive]

So dicit artem ... crescere is Latin’s normal way to express says that the skill grows.

A learner coming from English often wants to insert a word like quod for that, but with a straightforward reported statement, the accusative-and-infinitive construction is the standard choice.

Scribendi is the genitive singular gerund of scribere (to write).

A gerund is a verbal noun. In this sentence, scribendi means of writing.

So:

• ars scribendi = the art of writing
• ars bene scribendi = the art of writing well

This is a very common Latin pattern: a noun followed by a genitive gerund to express the ... of doing something.

Because Latin wants the idea the art of writing, not simply the art to write.

After a noun like ars, Latin commonly uses a genitive expression:

• ars dicendi = the art of speaking
• ars legendi = the art of reading
• ars scribendi = the art of writing

So scribendi is not just another form of the verb; it is a noun-like form meaning of writing.

English sometimes uses to write where Latin prefers a gerund or other noun-like structure.

Yes. Bene modifies the verbal idea inside scribendi.

So bene scribendi means of writing well.

Even though scribendi is a gerund, it still carries verbal meaning, so an adverb like bene can naturally go with it. This is very similar to English the art of writing well.

Usu is the ablative singular of usus, usus.

Here it is an ablative of means (or instrument), meaning roughly:

• by use
• through practice
• with practice

So usu paulatim crescere means that the skill grows through practice / by practice, gradually.

A literal-minded gloss might be to grow gradually by use, but more natural English is usually to improve gradually through practice.

Because Latin often uses the ablative by itself to express ideas that English expresses with a preposition.

Especially with means or instrument, Latin can simply use the ablative:

• gladio pugnat = he fights with a sword
• laboribus discimus = we learn through efforts
• usu crescere = to grow by use / through practice

So the lack of a preposition is normal Latin grammar.

Paulatim is an adverb meaning gradually / little by little.

It modifies crescere, so the sense is:

• to increase gradually
• to grow little by little

Latin word order is flexible, so paulatim does not have to stand right next to crescere. Even though usu paulatim crescere may feel spread out to an English speaker, the connection is clear: the growing happens gradually.

Both are possible ways to understand it.

Latin ars can mean:

• art
• skill
• technique

So artem bene scribendi can be understood as:

• the art of writing well
• the skill of writing well
• skill in good writing

Depending on context, English may sound more natural with skill rather than art, even though ars is the Latin word behind both ideas.

Because magistra is in the nominative singular, which is the normal case for the subject of the main verb.

So:

• magistra = the teacher (subject of dicit)
• dicit = says
• artem ... crescere = the reported statement

This gives the structure:

• The teacher says
• that the skill of writing well grows gradually through practice

A learner may briefly wonder whether artem is the subject of the whole sentence, but it is only the subject of the infinitive crescere inside the indirect statement.

The word order is normal, but Latin is much freer than English.

This sentence puts:

• Magistra first: the topic or subject
• dicit early: the main action
• crescere at the end: a very common place for an infinitive or main verbal idea in a clause

The modifiers are grouped in a sensible way:

• artem bene scribendi = the skill of writing well
• usu = by practice
• paulatim = gradually
• crescere = to increase

Latin could rearrange some of these words without changing the basic meaning, because the endings carry much of the grammar.

Yes, crescere basically means to grow, but it can also mean to increase or to develop.

With something abstract like ars (skill, art), the idea is not physical growth but improvement or development. So in natural English, you might translate it as:

• the skill gradually increases through practice
• the ability develops gradually with practice

So grow is the core meaning, but English often prefers increase or develop in this kind of sentence.