高くはない vs 高くない
What is the difference between 高くない and 高くはない? Japanese is a language where small differences in words can convey a number of different nuances. The meaning may be the same but have different implications. One example is when in Japanese you use the particle は with negative forms of adjectives. Let’s take a look.
https://japaneseuniverse.com/2024/02/18/pac-man-in-japaneseconcepts-behind-development-to-global-icon/INDEX
高くはない vs 高くない
First, 高くない means that something is not expensive.
この靴は高くはない
These shoes are not really that expensive
When you add は to it the meaning is the same but has new nuances about how not expensive it is. 高くはない means that something is not expensive, but it is not really cheap either. So, if someone says 高くはない they mean that it reasonable or it is not expensive in comparison to other things.
この靴は高くはない
These shoes are not really that expensive
Think of 高くはない as an Abbreviation
When someone says 高くはない they are implying that something is not really that expensive but not necessarily cheap.
この靴は高くはないが、そこまで安くない
These shoes are not really that expensive, but they aren’t cheap either
高くはある vs 高い
So, if you were curious, Japanese also has a positive form of 高くはない. If you say 高くはある it means that something is expensive but not that expensive.
この靴は高くはあるが、そこまで高くない
These shoes are expensive, but not that expensive
If you want to learn more Japanese I reviewed a dictionary of grammar series which I personally recommend and use myself.