Тональность слишком высокая.

In Russian, the verb to be is usually omitted in the present tense.

So:

• Тональность слишком высокая. literally: Tonality too high natural English: The tonality is too high.

This is completely normal in Russian. If you were speaking about the past or future, a form of быть would appear:

• Тональность была слишком высокой. = The tonality was too high.
• Тональность будет слишком высокой. = The tonality will be too high.

Because высокая has to agree with тональность in gender, number, and case.

• тональность is feminine
• singular
• nominative case

So the adjective must also be feminine singular nominative:

• masculine: высокий
• feminine: высокая
• neuter: высокое
• plural: высокие

Since тональность is feminine, the correct form is высокая.

A very common clue is the ending.

Тональность ends in -ость, and nouns ending in -ость are typically feminine in Russian.

Examples:

• скорость = speed
• возможность = possibility
• мягкость = softness
• тональность = tonality/key/tone quality, depending on context

Also, many feminine nouns in Russian end in the soft sign ь, and тональность belongs to that group.

Слишком means too in the sense of more than is acceptable or desired.

Here it modifies the adjective высокая:

• слишком высокая = too high

Its usual position is before the adjective or adverb it modifies:

• слишком высокая
• слишком громко
• слишком быстро

So in this sentence, слишком naturally comes before высокая.

It is in the nominative singular.

In this sentence, тональность is the subject: it is the thing being described as too high.

So the basic structure is:

• Тональность = subject
• слишком высокая = predicate description

Russian often uses the nominative for both the subject and the predicate adjective in this kind of present-tense sentence.

Yes. Russian word order is more flexible than English word order.

The neutral version is:

• Тональность слишком высокая.

But you could also say:

• Слишком высокая тональность.
• Высокая тональность.
• Тональность высокая.

The meaning stays similar, but the emphasis changes:

• Тональность слишком высокая. = neutral statement
• Слишком высокая тональность. = stronger focus on too high
• Тональность высокая. = simply The tonality is high

So word order in Russian often helps show focus rather than basic grammar.

Not always. Russian высокий / высокая / высокое often corresponds to English high, but the exact translation depends on context.

For example, it can describe:

• physical height: высокий дом = a tall/high building
• pitch: высокий звук = a high sound/note
• level or degree: высокая температура = high temperature
• style/register: sometimes more figurative meanings are possible

In this sentence, if the topic is music or sound, высокая most likely refers to something like too high in pitch/key/register.

It depends on context.

Тональность can mean:

• key in music
• tonality
• sometimes tone or tone quality in a broader technical or artistic sense

A learner may expect a more basic word like тон, but тональность is more specific and often more formal or technical.

So the sentence could be understood differently depending on the situation, for example:

• in music: The key is too high
• in audio/music theory: The tonality is too high

The main stresses are:

• тонАльность
• слишкОм
• высОкая

So a helpful pronunciation guide is:

• та-NAHL'-nast' slish-KOM vy-SO-ka-ya

A rougher English-style approximation would be:

• toh-NAHL-nust sleesh-KOHM vih-SOH-kah-yah

The stress matters in Russian, so it is useful to learn the stressed syllables together with each word.

Yes, but the meaning changes.

• очень высокая = very high
• слишком высокая = too high

So:

• Тональность очень высокая. = The tonality is very high.
• Тональность слишком высокая. = The tonality is too high.

Слишком implies a problem or excess. Очень does not necessarily imply that.

Because высоко is usually an adverb or a short-form predicative word meaning high in a different structure.

Here, the sentence describes a noun (тональность), so Russian uses the full adjective agreeing with that noun:

• тональность высокая = the tonality is high

Compare:

• Здесь высоко. = It is high here.
• Птица летает высоко. = The bird flies high.

So in your sentence, высокая is correct because it describes the feminine noun тональность.