tā shì wǒ de lǎo péngyou.

他 is pronounced tā with the first tone: high and level.

In modern written Chinese, 他 usually means he / him.
However, in spoken Mandarin, he, she, and it are all pronounced tā. The difference only shows up in writing:

• 他 = he
• 她 = she
• 它 = it

So if you only hear the sentence, you cannot tell from pronunciation alone whether it is he or she.

是 is the verb to be in this kind of sentence.

So:

• 他是我的老朋友 = He is my old/long-time friend

Here, 是 links the subject 他 and the noun phrase 我的老朋友.

A useful beginner pattern is:

• A 是 B = A is B

Examples:

• 我是学生 = I am a student
• 他是老师 = He is a teacher

No. This is a very common learner question.

Chinese uses 是 mainly when linking one noun or pronoun to another noun phrase.

For example:

• 他是医生 = He is a doctor

But with adjectives, Chinese usually does not use 是:

• 他很忙 = He is busy
  not 他是很忙

So in your sentence, 是 is used because 我的老朋友 is a noun phrase, not an adjective.

的 is a very common particle that often shows possession or a modifying relationship.

So:

• 我 = I / me
• 我的 = my

In this sentence:

• 我的老朋友 = my old friend / my long-time friend

You can think of 的 as doing a job similar to 's or of in English, though it is not exactly the same in every situation.

More examples:

• 他的书 = his book
• 老师的学生 = the teacher's student

Not necessarily. In 老朋友, 老 usually does not mean the friend is old in age.

Here, 老朋友 usually means:

• an old friend
• a long-time friend
• a friend you have known for a long time

So 老 here describes the relationship, not the person's age.

If you want to say someone is old in age, Chinese usually expresses that differently, depending on context.

Usually, learners should use 老朋友, not 旧朋友, for old friend.

• 老朋友 = a long-time friend
• 旧 often means old in the sense of used, former, or not new

So 旧朋友 is generally not the natural everyday way to say an old friend.

A good rule:

• for a long friendship, use 老朋友

Chinese word order here is very similar to English:

• 他 = he
• 是 = is
• 我的老朋友 = my old friend

So the structure is:

• subject + 是 + noun phrase

Inside 我的老朋友, the modifier comes before the noun:

• 我 的 modifies 朋友
• 老 also modifies 朋友

So Chinese builds the noun phrase as:

• my + old + friend
• 我的老朋友

The meaning changes because the subject changes.

• 他是我的老朋友 = He is my old friend
• 我是他的老朋友 = I am his old friend

Both sentences can be true, but they focus on different subjects.

This is a good reminder that Chinese depends heavily on word order.
The first noun before 是 is the topic/subject of the statement.

By itself, 朋友 can mean friend or friends depending on context.

In this sentence, because of the structure 他是我的老朋友, it is understood as singular:

• He is my old friend

If you want to make plural very clear, Chinese often adds words such as:

• 朋友们 = friends
• or uses context/numbers, such as 两个朋友 = two friends

But unlike English, Chinese nouns usually do not change form just to mark singular vs. plural.

朋友 is usually pronounced péngyou.

Important pronunciation point:

• 朋 = péng with the second tone
• 友 in this word is often read in a neutral tone, so it sounds lighter: you

So it is commonly said as:

• péngyou

rather than a strong full péngyǒu in careful citation style.

This neutral-tone pattern is very common in everyday Mandarin.

In standard Mandarin, 我的老朋友 is the normal form.

Saying 我老朋友 is generally not standard in careful speech.
For beginners, it is best to keep 的:

• 我的老朋友 = my old friend

Chinese sometimes omits 的 in certain modifier structures, but not all omissions are natural. In this sentence, keeping 的 is the safe and correct choice.

Yes. That is a very natural English translation.

Chinese 我的老朋友 can be translated as:

• my old friend
• a long-time friend of mine
• an old friend of mine

The exact English wording depends on style, but the Chinese sentence stays the same.

Yes. 老朋友 often has a warm, familiar feeling.

It suggests:

• a long relationship
• familiarity
• closeness
• shared history

So the sentence is not just identifying someone; it can also imply a friendly personal connection.

That is one reason 老朋友 is more natural than trying to translate old friend word-for-word in some other way.