הוא בדרך כלל מנומס, אבל כשהוא עייף הוא קצת עצלן ולא רוצה לעזור בבית.

In Hebrew, the verb to be is usually not stated in the present tense.

So:

• הוא מנומס = He is polite
• literally: He polite

The same thing happens later:

• הוא עייף = He is tired
• הוא קצת עצלן = He is a little lazy

But in past or future, Hebrew does use forms of to be when needed.

בדרך כלל means usually or generally.

Literally, it comes from:

• דרך = way
• כלל = general/rule

Together, בדרך כלל is a fixed expression meaning usually.

In this sentence:

• הוא בדרך כלל מנומס = He is usually polite

Its placement is very natural in Hebrew. You can think of it as sitting between the subject and the adjective. English learners often expect a direct word-for-word match, but Hebrew adverb placement is often a bit flexible.

They are all masculine singular forms, because they describe הוא (he).

Here is the agreement:

• הוא מנומס = he is polite
• הוא עייף = he is tired
• הוא עצלן = he is lazy

If the subject were feminine, the forms would change:

• היא מנומסת
• היא עייפה
• היא עצלנית

So Hebrew adjectives must agree with the noun or pronoun in gender and usually also number.

אבל means but.

It connects two contrasting ideas:

• הוא בדרך כלל מנומס = He is usually polite
• אבל כשהוא עייף... = but when he is tired...

So the sentence is showing a contrast:

• normally he behaves one way,
• but in a different situation, he behaves differently.

כשהוא means when he.

It is made from:

• כש־ = when
• הוא = he

So:

• כשהוא עייף = when he is tired

The הוא is needed because Hebrew normally says the subject explicitly here. Then later you get another הוא:

• כשהוא עייף הוא קצת עצלן
  = When he is tired, he is a little lazy

This repetition is normal. English can also repeat he in the same way.

Yes, קצת usually means a little, a bit, or somewhat.

So:

• קצת עצלן = a little lazy
• a bit lazy

It softens the statement. It sounds less harsh than simply saying:

• הוא עצלן = He is lazy

Very often, קצת is used in everyday Hebrew to make descriptions sound milder or more natural.

This is a very common Hebrew pattern:

• לא = not
• רוצה = wants
• לעזור = to help

So:

• לא רוצה לעזור = doesn’t want to help

A helpful pattern to remember is:

• רוצה + infinitive = wants to + verb

Examples:

• רוצה לאכול = wants to eat
• רוצה ללכת = wants to go
• רוצה לעזור = wants to help

And with negation:

• לא רוצה לאכול = doesn’t want to eat

Because after רוצה (wants), Hebrew normally uses the infinitive: to help.

The infinitive here is:

• לעזור = to help

This is the dictionary-style to + verb form in Hebrew.

So the structure is:

• הוא רוצה לעזור = He wants to help
• הוא לא רוצה לעזור = He does not want to help

This is similar to English.

בבית means at home or in the house, depending on context.

It is made of:

• ב־ = in / at
• בית = house / home

So:

• בבית literally = in the house
• but very often it naturally means at home

In this sentence, לעזור בבית is best understood as:

• to help at home
• or to help around the house

Not exactly word-for-word, but that is the basic idea.

In natural English, the best translation is usually:

• to help at home
• to help around the house

Hebrew often uses בבית in places where English prefers a more idiomatic phrase.

So although in the house is the literal meaning, the natural sense is more about helping with home responsibilities.

Yes:

• הוא = he
• בדרך כלל = usually
• מנומס = polite
• אבל = but
• כשהוא = when he
• עייף = tired
• הוא = he
• קצת = a little / a bit
• עצלן = lazy
• ולא = and not
• רוצה = wants
• לעזור = to help
• בבית = at home / in the house

So the full sentence is:

• הוא בדרך כלל מנומס, אבל כשהוא עייף הוא קצת עצלן ולא רוצה לעזור בבית.
• He is usually polite, but when he is tired he is a little lazy and doesn’t want to help at home.

You would need to change the pronoun and the adjective forms so they agree with a feminine subject:

• היא בדרך כלל מנומסת, אבל כשהיא עייפה היא קצת עצלנית ולא רוצה לעזור בבית.

Changes:

• הוא → היא
• מנומס → מנומסת
• עייף → עייפה
• עצלן → עצלנית

Notice that רוצה stays the same in writing here; in unpointed modern Hebrew, masculine and feminine singular present forms of many verbs can look the same.