WIn Japan, we call a bottle of spring water, a bottle of "mineral water in Japan."

The correction above is another way of writing the sentence to make it a little more clear what you're comparing.

The name of the term "mineral water" is verymore commonly used in Japan. than the term "spring water."

However, wWhen I mentioned "mineral water," however, an American did not understand to what I was referring to.

In more formal writing, we try to avoid beginning a sentence with "however." We also try to avoid ending a sentence with a preposition.

I was totally upset, because I thought that I couldn't make myself understood with my pronunciation at that time, at the time, I thought my pronunciation was keeping me from being understood.

The American told me later that so-called the term "mineral water wa" is not so commonlyoften used in America.

I'm not sure I agree with the statement the American here made. I feel a lot of us would've known what you meant.

It is called "spring water " or merely a "a bottle of water."

Cultural note: We usually call it "bottled water."

I thought it over forin the meantime being.

When thea Japanese company wanted to sell spring water for the first time, I'm sure the company was perplexed about how to sell it in Japan.

This phrase is incomplete without the next sentence.

I'm sure the company was perplexed about how to sell the water in Japan.

The wWater in Japan is free of charge and you are ableand everyone is allowed to drink it as well.

What kind of person in Japan wants to buy the water?

So the company named it something special like the "mineral water because it is supposed to contain much" to make it seem like the water had many more minerals than plain water in Japan.

EFor a long time, even I have believed that for a long timeit.

Stylistically, this is how we'd usually write or say it in the US.

LateRecently I learned that the plain water in Japan contained muchs many more minerals than a bottle ofd spring water imported from France.

The phrase in the clause after the word "that" is present tense because you're stating a fact.

I learned that the spring water imported from foreign countries and the spring water products in Japan are just plain water, and nothing special at all.

It's so laughable, isn't ridiculous, isn't it?¶
¶
or¶
¶
It's so ironic, isn't it?

We don't usually use the word "laughable." We usually use words like "ridiculous" or "ironic" or even "crazy" to describe a situation like this.

Spring Water and Mineral Water

I was totally upset, Bbecause I thought that I couldn't make myself understood with my pronunciation at that time.

The American told me later that so-called mineral water was not so commonly used in the America.

It is called a spring water or merely a bottle of water.

I thought it over it for athe time being.

When theUntil a Japanese company wanted to sell the spring waters for the first time.

I'm sure the company was perplexed about how to sell the water in Japan.

The water in Japan is free of charge, and byou are able to drink it as well.

What kind of persons in Japan would want to buy the water?

So the company named it something special like the mineral water whichbecause it is supposed to contain much more minerals than plain water in Japan.

Even I have believed that way for a long time.

Lately I came to knowlearned that the plain water in Japan contained minerals much more minerals than a bottle of spring water imported from France.

I came to know the learned that spring waters imported from foreign countries and products in Japan are just plain waters, and nothing special ones at all.

It's so laughable, isn't it?