ट्रेडमिल नई है।

A natural pronunciation is:

ṭreḍmil nayī hai

A rough English-friendly guide would be:

trayd-mill na-yee hai

A couple of notes:

• ट्रेडमिल is a borrowed English word written in Devanagari.
• नई is usually pronounced in two parts, roughly na-yee.
• है sounds like hai, not like English hey.

Here is the breakdown:

• ट्रेडमिल = treadmill
• नई = new
• है = is

So the structure is:

noun + adjective + is

That is a very common Hindi pattern for sentences like X is Y.

Because the noun is being treated as feminine singular in this sentence.

The adjective नया changes form to match gender and number:

• masculine singular: नया
• feminine singular: नई
• plural / some oblique forms: नए

So:

• कमरा नया है = The room is new.
• किताब नई है = The book is new.
• ट्रेडमिल नई है = The treadmill is new.

With many borrowed words, especially words that end in a consonant, the gender is not obvious from the form alone. You often have to learn it from usage.

In this sentence, ट्रेडमिल is clearly being treated as feminine because the adjective is नई.

A helpful way to think about it is:

• Hindi nouns have grammatical gender.
• Loanwords also get assigned a gender.
• Sometimes that gender must simply be memorized.

In real life, loanword gender can sometimes vary by speaker or region, but in this sentence the grammar is definitely feminine.

Both patterns exist, but they mean different things.

1. नई ट्रेडमिल
   = new treadmill
   Here the adjective is directly describing the noun inside a noun phrase.

2. ट्रेडमिल नई है
   = The treadmill is new
   Here नई is part of the predicate, and है completes the sentence.

So:

• नई ट्रेडमिल = a new treadmill
• ट्रेडमिल नई है = the treadmill is new

है is the present-tense form of to be for a singular subject in this kind of sentence. Here it means is.

So:

• ट्रेडमिल नई है = The treadmill is new.

If the subject were plural, Hindi would usually use हैं instead:

• ट्रेडमिलें नई हैं = The treadmills are new.

Hindi does not have articles like English a, an, and the.

So a sentence like ट्रेडमिल नई है can mean:

• The treadmill is new
• A treadmill is new

Which one sounds best depends on context. Usually the situation tells you whether the meaning is definite or indefinite.

In a full, normal sentence, you should keep है.

So the standard sentence is:

ट्रेडमिल नई है।

You may sometimes see or hear shortened forms without है in very informal speech, labels, ads, or headlines, but learners should treat है as necessary here.

Add नहीं before है:

ट्रेडमिल नई नहीं है।
= The treadmill is not new.

That is the normal Hindi pattern:

predicate + नहीं + है

For example:

• कमरा साफ़ नहीं है = The room is not clean.
• किताब नई नहीं है = The book is not new.

Yes. That means:

This treadmill is new.

Adding यह makes the noun more specific.

Compare:

• ट्रेडमिल नई है = The treadmill is new.
• यह ट्रेडमिल नई है = This treadmill is new.

Both are grammatical. The second one just adds this.

It is a normal form, but learners often notice it because it looks a little less transparent than some other adjective patterns.

The adjective is based on नया:

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

So नई is simply the feminine singular form of नया. It is very common, and you will see this pattern with other variable adjectives too.