Cette voyelle est claire, tandis que cette consonne est plus difficile à prononcer.

Because voyelle and consonne are both feminine singular nouns.

French demonstrative adjectives change according to gender and number:

• ce = this/that for masculine singular before most consonants
• cet = this/that for masculine singular before a vowel or mute h
• cette = this/that for feminine singular
• ces = these/those for plural

So:

• cette voyelle
• cette consonne

Both mean this vowel / this consonant.

It can mean either this or that, depending on context.

In everyday French, ce / cet / cette / ces do not always clearly distinguish between this and that the way English does. Very often, context tells you which one is meant.

If French speakers want to make the distinction more explicit, they can add:

• -ci = this
• -là = that

For example:

• cette voyelle-ci = this vowel
• cette consonne-là = that consonant

But in your sentence, simple cette is perfectly normal.

Because adjectives usually agree with the noun they describe.

Here, claire describes voyelle, which is feminine singular, so the adjective must also be feminine singular:

• masculine: clair
• feminine: claire

So:

• un son clair
• une voyelle claire

This is a very common French pattern.

Here claire means something like clear, distinct, or easy to hear/recognize.

With sounds or pronunciation, clair often suggests that something is:

• easy to distinguish
• well pronounced
• not confusing

So Cette voyelle est claire means the vowel sound is clear or distinct, not blurry or hard to identify.

Tandis que means while, and here it introduces a contrast between two ideas.

So the sentence is comparing the two parts:

• Cette voyelle est claire
• cette consonne est plus difficile à prononcer

In English, depending on style, you might translate tandis que as:

• while
• whereas
• while on the other hand

It is a bit more formal or literary than plain mais in some contexts.

Both can show contrast, but they do not work exactly the same way.

• mais = but
• tandis que = while / whereas

Mais is the most general and common way to say but:

• Cette voyelle est claire, mais cette consonne est plus difficile à prononcer.

Tandis que often sounds a little more like a side-by-side comparison:

• one thing is true,
• whereas another thing is different.

So in your sentence, tandis que helps set up a neat comparison between the vowel and the consonant.

Because French forms the comparative of most adjectives with:

• plus = more
• adjective

So:

• difficile = difficult
• plus difficile = more difficult

This is the normal way to say more difficult in French.

Examples:

• facile → plus facile
• long → plus long
• clair → plus clair

Because in French, adjectives like difficile, facile, simple, and agréable are often followed by à + infinitive.

So:

• difficile à prononcer = difficult to pronounce
• facile à comprendre = easy to understand
• simple à utiliser = simple to use

This is a very common structure.

In English, we say difficult to pronounce.
In French, the usual pattern is difficile à prononcer.

Because after difficile, French normally uses à in this type of construction.

So the natural expression is:

• difficile à prononcer

not:

• difficile de prononcer in this sentence

French does use de + infinitive in many other patterns, but with adjectives like difficile when they describe a thing as being hard to do something with, à + infinitive is the usual choice.

Compare:

• Cette consonne est difficile à prononcer.
• Il est difficile de prononcer cette consonne.

Both are possible, but they are structured differently:

1. Cette consonne est difficile à prononcer.
   = This consonant is difficult to pronounce.

2. Il est difficile de prononcer cette consonne.
   = It is difficult to pronounce this consonant.

The person doing the action is not stated explicitly. It is understood in a general sense: for someone / for people / for the speaker / for learners.

This is very common in both French and English.

So the sentence really means:

• This consonant is harder to pronounce
• that is, harder for someone to pronounce

French often leaves that kind of subject unstated when it is obvious or general.

Not in this sentence as it stands.

French normally needs a determiner before the noun, so you say:

• cette voyelle
• cette consonne

If you remove the second cette, the sentence becomes ungrammatical:

• Cette voyelle est claire, tandis que consonne... ❌

You could avoid repeating it only by changing the structure, for example with a pronoun:

• Cette voyelle est claire, tandis que celle-ci est plus difficile à prononcer.

But in your original sentence, repeating cette is the natural and correct choice.

In plus difficile, plus is normally pronounced ply.

So you do not usually pronounce the final s here.

Very roughly:

• plus difficile → ply di-fi-sil

This is because plus has different pronunciations depending on its use. In a comparative like more difficult, it is usually pronounced without the final s sound.

Yes, a few useful ones:

• cette sounds like set
• voyelle is roughly vwah-yel
• est is usually pronounced è
• claire sounds like klair
• in tandis que, the s in tandis is not pronounced
• consonne sounds roughly like kon-son
• plus difficile is usually ply di-fi-sil
• prononcer has a nasal vowel in the middle: roughly pro-non-say

A rough pronunciation of the whole sentence could be:

set vwa-yel è klair, tan-di kə set kon-son è ply di-fi-sil a პრო-non-say

That is only an approximation, but it can help as a starting point.