tomodati ha hausubooru wo tukau.

A natural reading is:

ともだち は ハウスボール を つかう。

Word by word:

• 友達 = ともだち
• は = pronounced wa here
• ハウスボール = hausu bōru
• を = pronounced o
• 使う = つかう

So the whole sentence sounds like:

ともだちは ハウスボールを つかう。

This is one of the most common beginner questions.

When は is used as the topic particle, it is pronounced wa, not ha.

So in this sentence:

• 友達は = tomodachi wa

Here, は marks 友達 as the topic, meaning something like:

• As for the friend, ...
• or more naturally in English, just The friend ... / My friend ... / A friend ..., depending on context.

This is a special pronunciation used only when は functions as a particle.

は marks the topic of the sentence.

In 友達はハウスボールを使う, the topic is 友達.

That means the sentence is talking about the friend and then saying something about that friend.

A rough structure is:

• 友達は = As for the friend,
• ハウスボールを使う = uses a house ball

So は does not directly mean a word like is or the. Its job is grammatical: it tells you what the sentence is about.

を marks the direct object of the verb.

In this sentence:

• ハウスボールを使う
• use a house ball

So ハウスボール is the thing being used, and を shows that relationship.

Even though it is written を, in modern Japanese it is usually pronounced simply o.

So:

• ハウスボールを = hausu bōru o

Katakana is commonly used for:

• loanwords from other languages
• foreign names
• some technical or emphasis-related writing

ハウスボール is a loanword from English house ball, a term often used in bowling for a ball provided by the bowling alley.

Because it is a borrowed word, it is written in katakana rather than hiragana or kanji.

Japanese word order is usually Subject/Topic - Object - Verb.

So this sentence follows a very common Japanese pattern:

• 友達は = topic
• ハウスボールを = object
• 使う = verb

Japanese verbs normally come at or near the end of the sentence.

That is why 使う appears last.

By itself, 友達 can mean:

• a friend
• friends

Japanese nouns usually do not change form for singular and plural the way English nouns often do.

So the exact number depends on context.

In this sentence, 友達は could mean:

• the friend
• a friend
• friends

If the meaning shown to the learner uses friend or friends, that comes from context, not from the noun form alone.

Japanese does not normally use articles like English a, an, and the.

So 友達 can mean:

• a friend
• the friend
• friends

And ハウスボール can mean:

• a house ball
• the house ball

Context tells you which one makes the most sense.

This is very normal in Japanese, so learners should get used to the idea that article information is often left unstated.

使う is the plain, non-past form.

That form can mean different things depending on context, such as:

• uses
• will use
• use(s) in a general or habitual sense

So 友達はハウスボールを使う could mean:

• My friend uses a house ball
• My friend will use a house ball
• Friends use house balls, depending on context

Japanese often relies on context more than English for tense interpretation.

Both は and が can mark something like the subject area of a sentence, but they are not the same.

In this sentence, は presents 友達 as the topic:

• As for the friend, ...

Using が would feel different. It would emphasize the friend as the one who does the action, often in a more specific or contrastive way depending on context.

Very roughly:

• 友達はハウスボールを使う。 = As for the friend, they use a house ball.
• 友達がハウスボールを使う。 = The friend is the one who uses a house ball.

For beginners, the key point is:

• は = topic
• が = subject marker with a different nuance

Yes. 使う is the dictionary form of the verb.

This form is also called the:

• plain form
• non-past plain form

You will often see dictionary forms in vocabulary lists and casual-style sentences.

If you wanted a polite version, it would be:

• 友達はハウスボールを使います。

So:

• 使う = plain
• 使います = polite

Yes. Japanese often leaves out information that is understood from context.

For example, if everyone already knows you are talking about your friend, someone might simply say:

• ハウスボールを使う。

That could still be understood as:

• (My friend) uses a house ball
• or (I) use a house ball
• or someone else, depending on context

In the full sentence you gave, the topic and object are both clearly stated, which makes it a good learning example.