El seu rellotge és sobre la taula.

Yes, seu is a possessive, but Catalan normally uses the definite article + possessive + noun pattern:

el seu rellotge = his/her/your/their watch

This is very common in Catalan:

• el meu llibre = my book
• la seva casa = his/her house

So unlike English, Catalan usually does not drop the article here.

Seu is a possessive meaning his, her, its, your (formal singular), or their, depending on context.

So El seu rellotge could mean:

• his watch
• her watch
• its watch
• your watch (formal)
• their watch

Catalan often leaves this ambiguous unless the context makes it clear. If you need to be very specific, Catalan can use forms like:

• el rellotge d’ell = his watch
• el rellotge d’ella = her watch
• el rellotge d’ells = their watch

It agrees with the thing possessed, not with the owner.

Here, rellotge is masculine singular, so the possessive is seu.

Compare:

• el seu rellotge = his/her watch
• la seva taula = his/her table
• els seus llibres = his/her books
• les seves claus = his/her keys

So the form changes to match the noun being described.

In Catalan, ser is often used for simple location, especially in neutral statements like this one.

So:

• El seu rellotge és sobre la taula. = His/her watch is on the table.

English speakers often expect estar because of Spanish, but Catalan uses ser more broadly for location.

That said, in some contexts or varieties, està can also appear, especially if you want to emphasize the current position or situation. But és is completely normal and standard here.

The accent in és serves two purposes:

1. It shows the stressed vowel.
2. It distinguishes és = is from es = a reflexive/pronominal form, like himself/herself/itself in some contexts.

So:

• és = is
• es = reflexive pronoun

The accent is important and should be written.

Here, sobre means on or on top of.

So:

• sobre la taula = on the table

Depending on context, sobre can also mean about/concerning, but not in this sentence.

In everyday Catalan, many speakers also use:

• a sobre de la taula
• damunt de la taula

These also mean on the table / on top of the table.

Catalan usually uses the article with nouns in this kind of phrase.

So:

• sobre la taula = on the table

Here, taula is a feminine singular noun, so it takes la.

This is similar to how Catalan normally marks nouns with articles more consistently than English does.

• rellotge is masculine singular
• taula is feminine singular

That matters because articles and possessives must agree with the noun:

• el seu rellotge
• la taula

So the sentence shows two agreement patterns:

• el matches rellotge
• la matches taula
• seu also matches rellotge

Rellotge can be tricky for English speakers.

A rough approximation is: reh-YOJ-juh or reh-YOJ-che, depending on accent and variety.

A few helpful points:

• ll in Catalan is often like a soft ly sound in some varieties, though pronunciation varies.
• The ending -tge sounds like the sound in English judge, but again it can vary by dialect.

You do not need a perfect pronunciation immediately, but it is definitely a word worth practicing because the spelling is not very transparent for English speakers.

Yes. That is a very natural alternative.

These are all possible:

• El seu rellotge és sobre la taula.
• El seu rellotge és a sobre de la taula.
• El seu rellotge és damunt de la taula.

All mean basically His/her watch is on the table.

The version with a sobre de is especially common in everyday speech.