المطحنة بتغير درجة الطحن.

A natural pronunciation is roughly:

el-maTḥana bitghayyar daragit iT-Taḥn

A few notes:

• المطحنة = el-maTḥana / el-maṭḥana
• بتغير here is bitghayyar = changes / is changing
• درجة is often heard as daragit before another noun
• الطحن is pronounced more like iT-Taḥn because the ل of الـ merges into ط

In Egyptian Arabic, بـ on a verb usually marks the normal present tense.

So:

• تغيّر = change
• بتغيّر = changes / is changing

In this sentence, بتغير means it changes or it adjusts/changes.

Because المطحنة is grammatically feminine.

Many nouns ending in ـة are feminine, and مطحنة ends that way. So the verb agrees with it:

• هي بتغير = it/she changes
• هو بيغير = it/he changes for a masculine noun

So المطحنة بتغير is the correct agreement.

Yes. On its own, بتغير can also mean you change when speaking to one female.

So the form can mean:

• she/it changes
• you (singular feminine) change

Here, the subject المطحنة makes it clear that the meaning is the grinder changes.

Because this is an iDaafa construction, often called a possessive or noun-linking structure.

درجة الطحن literally means:

• degree of grinding

In Arabic, in this structure:

• the first noun usually does not take الـ
• the second noun can make the whole phrase definite

So:

• درجة الطحن = the grind degree / the grinding level not
• الدرجة الطحن

Literally, it means the degree of the grinding.

In more natural English, depending on context, it could be:

• grind size
• grind setting
• grinding level

So even if the wording is literal in Arabic, the real-life meaning is often something like grind setting.

Because when a word ending in ـة is followed by another noun in an iDaafa phrase, that ending is often pronounced.

So:

• by itself: درجة → roughly daraga / daraga(h)
• in درجة الطحن: often daragit iT-Taḥn

This is very common in both Egyptian and Standard Arabic-type pronunciation patterns.

Because ط is a sun letter.

With sun letters, the ل in الـ is not pronounced separately. Instead, it merges into the next consonant.

So:

• written: الطحن
• pronounced: iT-Taḥn or eT-Taḥn

This is the same pattern you see in words like:

• الشمس → ish-shams
• الطالب → iT-Taalib

Because in Egyptian Arabic, subject + verb order is very common in everyday speech.

So:

• المطحنة بتغير درجة الطحن sounds natural and conversational

Starting with the noun also makes the grinder the topic of the sentence.

Compared with more formal Arabic, Egyptian often prefers this kind of word order.

It can mean either one, depending on context.

In Egyptian Arabic, the present form with بـ often covers:

• habitual meaning: changes
• ongoing meaning: is changing

In this sentence, the most likely meaning is a general one:

• the grinder changes the grind setting or
• the grinder can change the grind setting

A common negated version would be:

المطحنة ما بتغيرش درجة الطحن.

This uses the Egyptian negative pattern:

• ما ... ش

So:

• بتغير = changes
• ما بتغيرش = does not change

المطحنة can mean:

• the grinder
• the mill
• the grinding machine

The exact English choice depends on context. In a coffee context, the grinder is probably the most natural translation.