कॉलर नया है और पट्टा मज़बूत है।

Because this sentence is using नया as a predicate adjective: the collar is new.

In Hindi:

• नया कॉलर = a new collar or the new collar
• कॉलर नया है = the collar is new

So when the adjective is part of a description with है, it commonly comes after the noun.

Because the sentence is really two connected clauses:

• कॉलर नया है
• पट्टा मज़बूत है

They are joined by और meaning and. Hindi normally keeps है in each clause, just as English would normally say the collar is new and the strap is strong.

Because each clause has a singular subject:

• कॉलर = singular
• पट्टा = singular

So each one takes है.

If you made one combined plural subject, then you could use हैं, for example:

• कॉलर और पट्टा नए हैं = The collar and the strap are new

But that is a different structure from the sentence you were given.

It is a very common loanword from English. Hindi often uses English-origin words in everyday speech, especially for modern objects or familiar items.

So कॉलर is basically collar written in Devanagari. This is very normal in Hindi.

You can tell from the agreement with नया.

The adjective नया is the masculine singular form. So in this sentence, कॉलर is being treated as a masculine singular noun.

With many Hindi nouns, especially borrowed ones, gender often just has to be learned from usage. Agreement words like adjectives and verbs are often your best clue.

Because नया agrees with a masculine singular noun.

The basic pattern is:

• masculine singular: नया
• feminine singular: नई
• masculine plural: नए

So here:

• कॉलर नया है because कॉलर is masculine singular

If the noun were feminine, you would use नई, for example:

• कमीज़ नई है = The shirt is new

Because not all Hindi adjectives behave the same way.

Some adjectives are variable and change form for gender/number, like नया:

• नया
• नई
• नए

But some adjectives are invariable and usually stay the same, like मज़बूत.

So you can say:

• पट्टा मज़बूत है
• रस्सी मज़बूत है
• पट्टे मज़बूत हैं

The adjective मज़बूत stays the same, while the verb changes as needed.

और means and.

It connects the two parts of the sentence:

• कॉलर नया है
• पट्टा मज़बूत है

So the structure is very straightforward:

A + and + B

Hindi uses और much like English uses and.

पट्टा is a general word for something like a strap, band, or belt-like piece. Depending on context, it can sometimes be understood as:

• strap
• belt
• leash
• band

So the exact English word can change with context. In a sentence with कॉलर, it may suggest a strap or leash-related part.

Yes, but it means something slightly different grammatically.

• नया कॉलर = new collar
  This is just a noun phrase.
• कॉलर नया है = the collar is new
  This is a full sentence.

So both are correct, but they are used in different structures.

You would usually change the nouns and the verb, and sometimes the adjective too.

For example:

• कॉलर नए हैं और पट्टे मज़बूत हैं।

Here:

• कॉलर is plural in meaning from context
• नए is the masculine plural form of नया
• पट्टे is plural of पट्टा
• हैं is plural

Notice that मज़बूत still does not change.

That dot is called a nukta. It changes the sound of the letter.

• ज is usually like j in jam
• ज़ is like z in zoo

So मज़बूत is pronounced with a z sound, not a j sound.

This is common in words that came into Hindi through Persian, Arabic, Urdu, or modern borrowing patterns.