kono sensei wa hanashiyasui node, kigaru ni soudan dekimasu.

This teacher is easy to talk to, so I can consult her casually.

Breakdown of kono sensei wa hanashiyasui node, kigaru ni soudan dekimasu.

• は: topic particle
• 話はなす: to talk
• 先せん生せい: teacher
• この: this

Questions & Answers about kono sensei wa hanashiyasui node, kigaru ni soudan dekimasu.

Why is it この先生 and not このの先生?

この is a determiner, not a noun. It directly modifies the noun that follows it.

• この先生 = this teacher
• この本 = this book

You only use の when one noun modifies another noun, such as:

• 日本の先生 = a teacher from Japan / Japanese teacher
• 私の先生 = my teacher

So この先生 is the normal form.

What does は do in この先生は?

は marks この先生 as the topic of the sentence.

So the sentence is talking about this teacher, and then saying something about them:

• この先生は話しやすい = As for this teacher, they are easy to talk to

It does not necessarily mean strong contrast here; it mainly sets the topic.

How is 話しやすい formed?

話しやすい is made from:

• 話す = to speak, to talk
• verb stem 話し
• やすい = easy to do

So:

• 話す → 話しやすい = easy to talk to / easy to talk with

This pattern is very common:

• 読みやすい = easy to read
• 使いやすい = easy to use
• 分かりやすい = easy to understand