kono hutatu no kaban ha dotira mo karukute benri desu.

Japanese noun phrases are built differently from English.

この二つのかばん breaks down as:

• この = this / these
• 二つ = two
• の = linking particle
• かばん = bag(s)

So the whole phrase means these two bags.

A very literal way to think of it is something like these two bags or the two bags here. Japanese often puts the demonstrative first, then the number expression, then の, then the noun.

So:

• このかばん = this bag
• 二つのかばん = two bags
• この二つのかばん = these two bags

二つ is one of the general native Japanese counting words, and it is often used for ordinary objects when no special counter is needed.

For bags, Japanese speakers can use several ways of counting depending on context, but 二つ is very natural and easy.

Some possibilities are:

• 二つのかばん = two bags
• 二個のかばん = two bags, focusing on them as physical items
• sometimes a more specific counter may be used in certain contexts

For learners, 二つ is a very common and safe choice for everyday objects.

Here, の connects the quantity expression 二つ to the noun かばん.

So:

• 二つ = two
• かばん = bags
• 二つのかばん = two bags

You can think of this の as a linker that lets a number expression modify a noun.

You see the same pattern in many other phrases:

• 三つのりんご = three apples
• 一人の学生 = one student
• 五本のペン = five pens

は marks the topic of the sentence: what the sentence is talking about.

In this sentence, the topic is:

この二つのかばん = these two bags

Then the rest of the sentence says something about them:

どちらも軽くて便利です = both are light and convenient

So the overall structure is:

• この二つのかばんは = as for these two bags,
• どちらも軽くて便利です = both are light and convenient

This is a very common Japanese pattern:
Topic + は + comment

どちら usually means which one of the two.
But when you add も, it becomes both.

So:

• どちら = which one? / which of the two?
• どちらも = both

In this sentence, どちらも means that the statement applies to both bags.

So the speaker is saying that:

• bag A is light and convenient
• bag B is also light and convenient

A casual version would often be どっちも, but どちらも is more polite.

Both can mean both, but they are used a little differently.

• どちらも strongly suggests both of two options
• 両方 also means both, and is very common

So this sentence could also be expressed with 両方 in many situations. But どちらも fits especially well when the speaker is talking about exactly two items and treating them as two alternatives in comparison.

Very roughly:

• どちらも軽くて便利です = both of the two are light and convenient
• 両方とも軽くて便利です = both are light and convenient

Both are natural, but どちらも has a nice of the two feeling.

軽い is an i-adjective meaning light.
To connect it to another description, it changes to the -て form:

• 軽い → 軽くて

This is how Japanese links adjectives, similar to light and convenient in English.

So:

• 軽くて便利です = light and convenient

The -て form here works like and. It can sometimes also suggest a reason, but in this sentence it is most naturally just linking two qualities.

Other examples:

• 安くて便利です = cheap and convenient
• 大きくてきれいです = big and pretty

便利 is a na-adjective.

With na-adjectives, な is used only when the adjective directly modifies a noun:

• 便利なかばん = a convenient bag

But when the adjective comes at the end of the sentence, you do not use な:

• かばんは便利です = the bag is convenient

So in your sentence:

• 軽くて便利です = light and convenient

not 軽くて便利なです

Because 便利 is the final adjective in the sentence.

When a na-adjective is followed by another adjective or clause, it often takes で to connect:

• 便利で丈夫です = convenient and durable

But in this sentence, 便利 is the last descriptive word before です, so it stays as:

• 便利です

The connection already happened earlier with 軽くて:

• 軽くて = light and...
• 便利です = convenient

The -て form can sometimes express either:

• simple connection: and
• a loose reason: because

So 軽くて便利です could theoretically be interpreted as:

• it is light and convenient
• or, in some contexts, it is convenient because it is light

However, in this sentence the most natural reading is simply light and convenient.

Context decides which nuance is stronger.

です makes the sentence polite.

So:

• 便利です = is convenient / are convenient

Without です, the sentence would sound less polite or incomplete in normal standard speech.

This sentence uses polite style throughout, which matches どちらも nicely as well.

By itself, かばん does not show singular or plural the way English nouns do.

Japanese nouns often stay the same whether they mean one or more:

• かばん = bag / bags

In this sentence, the number is made clear by 二つ, so we know it means two bags.

That is why Japanese does not need a special plural form here.

Not very naturally. A very literal breakdown is:

• この二つのかばんは = as for these two bags
• どちらも = both
• 軽くて = light and
• 便利です = are convenient

A smoother English translation is:

These two bags are both light and convenient.

Japanese and English organize information differently, so a natural translation is better than a strict word-for-word one.