اللثة سليمة.

With full vowels, it is اللِّثَةُ سَلِيمَةٌ.

A careful MSA pronunciation is roughly:

• al-li-tha-tu sa-lee-ma-tun

A more natural paused pronunciation, without full case endings, is often closer to:

• al-litha salīma

Useful notes:

• ث sounds like th in think
• سليمة has a long ī sound, like ee in see
• The final ة is often heard as -a / -ah in pause, but it becomes -t when fully inflected

Because Arabic often leaves out the verb to be in the present tense.

So اللثة سليمة literally looks like:

• the gum healthy

but it means:

• The gum is healthy.

If you wanted a past or future meaning, Arabic would use a verb:

• كانت اللثة سليمة = The gum was healthy
• ستكون اللثة سليمة = The gum will be healthy

Because اللثة is a feminine noun, so the adjective has to match it.

• لثة = a feminine noun
• feminine adjective: سليمة
• masculine adjective: سليم

So:

• اللثة سليمة = correct
• اللثة سليم = incorrect

This kind of agreement is very important in Arabic: adjectives normally match the noun in gender.

Because this is a complete sentence, not just a noun phrase.

• اللثة = the gum → definite
• سليمة = healthy → predicate of the sentence

So اللثة سليمة means:

• The gum is healthy

But if you say اللثة السليمة, that means:

• the healthy gum

That is just a noun + adjective phrase, not a full sentence.

The difference is very important:

• اللثة سليمة = The gum is healthy.
  • This is a sentence
• اللثة السليمة = the healthy gum
  • This is a noun phrase

In Arabic, one clue is definiteness:

• In a sentence like this, the predicate adjective is often indefinite
• In a noun phrase, the adjective matches the noun in definiteness, so both are definite

سليمة means something like:

• healthy
• sound
• intact
• unaffected
• free from damage

In a medical or dental context, healthy is usually the best translation.

It comes from the root س-ل-م, which carries meanings related to being safe, sound, or unharmed. This is the same root you see in words like:

• سلام = peace
• سليم = sound, healthy, unharmed

Yes, اللثة is grammatically singular.

So this sentence literally means:

• The gum is healthy

But in real medical context, Arabic can use the singular to talk about the gum tissue in general, where English might naturally say the gums.

If you want a clearly plural form, you would use a plural noun, such as:

• اللثات سليمة = The gums are healthy

So the sentence you have is singular in form, but context may make it feel more general.

With full case endings, the sentence is:

• اللِّثَةُ سَلِيمَةٌ

Both words are in the nominative case:

• اللِّثَةُ = the subject (mubtadaʾ)
• سَلِيمَةٌ = the predicate (khabar)

So the endings are:

• ـُ on اللثة
• ـٌ on سليمة

In most everyday writing, these endings are not written, so you usually just see:

• اللثة سليمة

Because of the الـ article plus the first letter of the noun.

The base word is:

• لثة

When you add الـ, the result is:

• اللثة

Since the noun itself begins with ل, the l sound is effectively doubled in pronunciation.

So you hear something like:

• al-litha

not a clearly separated al + l...

This is a normal feature of Arabic pronunciation with the definite article.

That letter is taa marbuuTa: ة.

In this sentence, both اللثة and سليمة end in ة.

Its pronunciation depends on how fully you are reading:

• In pause or everyday citation, it usually sounds like -a / -ah
  • اللثة سليمة → al-litha salīma
• In fully inflected formal reading, it is pronounced with t
  • اللِّثَةُ سَلِيمَةٌ → al-li-tha-tu sa-lee-ma-tun

So both pronunciations are connected to the same spelling and grammar.