On chine ensemble et déniche un objet en porcelaine.

In this sentence, on most naturally means we.

Although on originally means something like one or people in general, in everyday spoken French it very often replaces nous. So:

• On chine ensemble = We go bargain-hunting / antique-hunting together
• On déniche un objet en porcelaine = We find / dig up a porcelain object

So even though on can sometimes mean people or someone, here it is understood as we.

Because on always takes third-person singular verb forms, even when it means we.

So you get:

• on chine
• on déniche

not:

• on chinons
• on dénichons

This is one of the most important things to remember about on:
its meaning may be plural, but its grammar is singular.

No. In a sentence like this, it is perfectly normal to say:

• On chine ensemble et déniche un objet en porcelaine.

The subject on applies to both verbs. French often omits the repeated subject when the same subject continues with et.

You could also say:

• On chine ensemble et on déniche un objet en porcelaine.

That version is also correct, but it sounds a little more explicit or slightly heavier. The version without the second on is very natural.

Chiner is a specific verb. It does not just mean to shop.

It usually means things like:

• browsing flea markets
• hunting for second-hand treasures
• looking through antiques or vintage goods
• bargain-hunting for interesting old objects

So chiner suggests a kind of enjoyable searching, often for unusual, old, or decorative items.

That is why it works well with un objet en porcelaine. The sentence gives the feeling of wandering around and finding a nice piece.

Dénicher means more than simply to find.

It often suggests:

• finding something after searching
• uncovering something interesting
• spotting a good or rare item
• digging up a little treasure

So:

• trouver = to find
• dénicher = to discover, track down, or dig up something special

In this sentence, dénicher fits the idea of chiner very well. It gives a sense of successful treasure-hunting.

Ensemble means together.

Here it tells you that the action of chiner is done jointly:

• On chine ensemble = We browse/hunt together

Its position is very natural after the verb. French adverbs like ensemble are often placed this way.

In French, en is commonly used to indicate the material something is made of, especially in simple descriptions.

So:

• un objet en porcelaine = a porcelain object
• literally, an object in porcelain

This is the normal way to say it.

De porcelaine is less natural here. In many cases, de can also indicate material, but en is especially common when describing what a physical object is made from.

Other examples:

• une table en bois = a wooden table
• une bague en or = a gold ring
• une tasse en céramique = a ceramic cup

Objet is a broad noun meaning object or item. It is often used when the speaker does not want to specify exactly what the thing is.

So un objet en porcelaine could be:

• a vase
• a figurine
• a plate
• a cup
• a decorative piece

You would not usually say une porcelaine to mean just any porcelain item. La porcelaine normally refers to the material itself, or sometimes porcelain ware in a broader sense.

It sounds fairly natural and everyday, especially because of:

• on meaning we
• the verbs chiner and dénicher, which are vivid and slightly expressive

It is not slang, but it is not especially formal either. A more neutral version might be something like:

• Nous cherchons ensemble et trouvons un objet en porcelaine.

But that sounds flatter and less idiomatic. The original sentence has more personality.

Yes, grammatically it can. For example:

• En France, on mange tard. = In France, people eat late.
• On ne sait jamais. = You never know.

But in your sentence, because of ensemble and the context of doing an activity together, on is most naturally understood as we, not people in general.

A careful approximate pronunciation would be:

On chine ensemble et déniche un objet en porcelaine.
on sheen ahn-sahmbl ay day-neesh uh-no-bzhay ahn por-seh-len

A few useful pronunciation points:

• on has a nasal vowel
• chine sounds like sheen
• ensemble begins with a nasal vowel too
• déniche sounds like day-neesh
• in natural speech, un objet may sound smoothly linked together

You do not need to pronounce every final consonant. French rhythm is generally smoother and more connected than English.