Nel titolo metto la maiuscola solo sulla prima parola.

Nel is the contraction of in + il.

• in = in
• il = the
• nel = in the

So Nel titolo means In the title.

Italian often combines prepositions and articles into one word:

• in + il = nel
• su + la = sulla
• a + il = al
• di + il = del

This is very common and something you will see all the time.

Titolo means title.

It is a masculine noun:

• il titolo = the title

So:

• Nel titolo = In the title

In this sentence, it refers to the capitalization style used for a title.

Metto is the first-person singular present tense of mettere, which usually means to put.

Here, though, mettere is being used in a broader sense: to put/use/apply.

So metto la maiuscola literally means something like I put the capital letter, but in natural English it means:

• I capitalize
• I use a capital
• I put a capital letter

Useful forms of mettere in the present tense:

• io metto = I put
• tu metti = you put
• lui/lei mette = he/she puts
• noi mettiamo = we put
• voi mettete = you all put
• loro mettono = they put

La maiuscola means the capital letter or capitalization, depending on context.

Italian often uses maiuscola by itself as a noun, even though originally it is also an adjective meaning uppercase/capital.

For example:

• scrivere in maiuscolo = to write in uppercase
• mettere la maiuscola = to use a capital letter
• lettera maiuscola = capital letter

So in this sentence, metto la maiuscola means I capitalize or more literally I put a capital letter.

Italian uses articles more often than English does.

So where English might simply say I capitalize the first word, Italian may say I put the capital letter only on the first word.

That is why la appears in la maiuscola:

• la maiuscola = the capital letter / the uppercase

This is normal Italian usage and does not sound overly literal to native speakers.

It means only on the first word.

Breaking it down:

• solo = only
• sulla = on the
• prima parola = first word

So:

• solo sulla prima parola = only on the first word

The idea is that in a title, the speaker uses a capital letter only for the first word, not for every important word as is common in English title style.

Sulla is the contraction of su + la.

• su = on
• la = the
• sulla = on the

So:

• sulla prima parola = on the first word

Here su works naturally with mettere, as in put something on a word.

Because parola is a feminine noun:

• la parola = the word

Adjectives must agree with the noun they describe, so:

• primo is masculine singular
• prima is feminine singular

Therefore:

• la prima parola = the first word

Compare:

• il primo titolo = the first title
• la prima parola = the first word

Because solo is modifying that whole phrase: on the first word only.

So:

• metto la maiuscola solo sulla prima parola

means that the limitation applies to where the capital letter goes.

In other words, the speaker is saying:

• I put the capital only on the first word
• not on the second, third, etc.

Italian word order is somewhat flexible, but this placement is very natural.

Yes, very likely.

In English, titles are often written in title case, where many main words begin with capitals:

• The Lord of the Rings

In Italian, titles are much more often written in sentence case, where normally only the first word is capitalized, unless another word is a proper noun:

• Il signore degli anelli

So this sentence reflects a common Italian convention:

• Nel titolo metto la maiuscola solo sulla prima parola.
• In the title, I capitalize only the first word.

Yes, you could, but it sounds more explicit.

Compare:

• metto la maiuscola = I use a capital / I capitalize
• metto la lettera maiuscola = I put the capital letter

The shorter version, la maiuscola, is very common and natural.

Yes, but moving solo can slightly change the emphasis.

For example:

• Metto la maiuscola solo sulla prima parola.
  = I put the capital only on the first word.

• Solo nel titolo metto la maiuscola sulla prima parola.
  = Only in the title do I capitalize the first word.

• Metto solo la maiuscola sulla prima parola.
  = This sounds less natural here, and it may suggest that the only thing I put on the first word is a capital letter.

So the original placement is the clearest and most natural for the intended meaning.

Yes.

It can be:

1. a noun

   • la maiuscola = the capital letter / uppercase

2. an adjective

   • una lettera maiuscola = a capital letter
   • iniziale maiuscola = capital initial

So in this sentence, maiuscola is being used as a noun.

Yes: the combination mettere la maiuscola is very useful.

You can use it in many everyday contexts:

• Metti la maiuscola all’inizio. = Put a capital letter at the beginning.
• Qui ci vuole la maiuscola. = A capital letter is needed here.
• I nomi propri vogliono la maiuscola. = Proper nouns take a capital letter.

So a good pattern to remember is:

• mettere la maiuscola su + word/expression
• to capitalize a word/expression