Lass bitte das Glas auf dem Tisch stehen.

Lass is the imperative form of lassen for du.

In German, commands often omit the subject pronoun. So:

• Du lässt ... = you let / you leave ...
• Lass ... ! = Leave ... !

So the sentence is speaking directly to one person in an informal way.

Compare:

• Lass bitte das Glas auf dem Tisch stehen. = informal, to one person
• Lasst bitte das Glas auf dem Tisch stehen. = informal, to several people
• Lassen Sie bitte das Glas auf dem Tisch stehen. = formal

Yes, lassen often means to let or to allow, but it has several common uses.

Here, lassen means something like:

• to leave
• to not change
• to keep something as it is

So das Glas auf dem Tisch stehen lassen means to leave the glass standing on the table.

This is a very common German pattern:

• etwas liegen lassen = leave something lying
• etwas stehen lassen = leave something standing
• etwas hängen lassen = leave something hanging

So in this sentence, lassen does not mean allow in the usual English sense. It means don’t move it; leave it there.

Because lassen is being used with another verb in the infinitive.

The structure is:

• lassen + object + infinitive

So here:

• Lass = imperative verb
• das Glas = object
• auf dem Tisch = location
• stehen = infinitive at the end

This is normal German word order.

You can think of it as:

• Leave the glass standing on the table

German often puts the second verb, especially an infinitive, at the end.

Because das Glas is the direct object of lassen, so it is in the accusative case.

Luckily, for das-words, nominative and accusative look the same:

• nominative: das Glas
• accusative: das Glas

So the form does not change, but the function is accusative.

You can see it more clearly with a masculine noun:

• Lass bitte den Teller auf dem Tisch stehen.

Here der Teller becomes den Teller in the accusative.

Because auf is a two-way preposition. With these prepositions, German uses:

• dative for location: where something is
• accusative for direction/movement toward a place

Here the glass is already on the table, and the sentence says to leave it there. So this is location, and German uses the dative:

• auf dem Tisch = on the table

Compare:

• Stell das Glas auf den Tisch. = Put the glass onto the table.
  (movement to the table, so accusative)
• Das Glas steht auf dem Tisch. = The glass is on the table.
  (location, so dative)
• Lass das Glas auf dem Tisch stehen. = Leave the glass on the table.
  (location, so dative)

German uses position verbs more often and more literally than English does.

A glass in an upright position is said to stehen in German. So:

• Das Glas steht auf dem Tisch. = The glass is on the table.

German often chooses different verbs depending on the object’s position:

• stehen = stand upright
• liegen = lie / be lying
• sitzen = sit
• hängen = hang

So for a glass, bottle, cup, chair, etc., stehen is very natural.

English often just uses be:

• The glass is on the table.

German is more specific here.

Yes, very often it is.

Stehen lassen commonly means:

• to leave standing
• to leave where it is
• sometimes to leave unfinished in certain contexts

In your sentence, it means leave it there; don’t move it.

Examples:

• Lass die Flasche bitte stehen. = Please leave the bottle where it is.
• Er hat sein Getränk halb voll stehen lassen. = He left his drink half full.

So learners should treat stehen lassen as a very common combination.

Bitte makes the command more polite. It means please.

Without bitte, the sentence is still grammatical:

• Lass das Glas auf dem Tisch stehen.

But with bitte, it sounds softer and more natural in many everyday situations:

• Lass bitte das Glas auf dem Tisch stehen.

German uses bitte very often in requests and commands.

Yes. Bitte is quite flexible.

All of these are possible:

• Lass bitte das Glas auf dem Tisch stehen.
• Lass das Glas bitte auf dem Tisch stehen.
• Bitte lass das Glas auf dem Tisch stehen.

The meaning stays basically the same, though the emphasis may shift slightly.

For a learner, the version in your sentence is completely natural.

Usually, German prefers stehen here.

If you say only:

• Lass das Glas auf dem Tisch

many native speakers will feel that something is missing, or they may interpret it differently depending on context.

With stehen, the meaning is clear:

• Leave the glass standing on the table
• Don’t move it from the table

So stehen is important because it completes the lassen + infinitive structure and makes the sentence sound natural.

Yes, it is informal singular, because Lass is the du imperative.

Formal version:

• Lassen Sie bitte das Glas auf dem Tisch stehen.

Informal plural version:

• Lasst bitte das Glas auf dem Tisch stehen.

So the choice depends on who you are talking to:

• Lass = one person, informal
• Lasst = more than one person, informal
• Lassen Sie = formal

In this context, yes, that is very close.

The idea is:

• the glass is on the table
• the speaker wants it to remain there

So possible English translations include:

• Please leave the glass on the table.
• Please don’t move the glass from the table.
• Please don’t take the glass away.

The exact English wording can vary, but the German grammar specifically expresses leave it there in that position.