La pumpilo estas apud la rado.

The suffix -il- usually means tool, instrument, or device used for doing something.
So:

• pumpi = to pump
• pumpilo = a pump, a device for pumping

This is very common in Esperanto word-building and helps learners recognize meaning quickly.

Estas is the present tense of esti, meaning to be. In this sentence it means is.

So:

• esti = to be
• estas = is / am / are

Esperanto uses the same form estas for all persons:

• mi estas = I am
• vi estas = you are
• ĝi estas = it is

Apud is a preposition meaning next to, beside, by, or at the side of. In this sentence, it shows location: the pump is beside the wheel.

It usually suggests closeness, not necessarily contact.

Normally, after a preposition like apud, the noun does not take -n when it simply shows location.

So:

• apud la rado = next to the wheel

The -n ending is mainly used for:

1. the direct object
2. direction/motion toward something in some expressions

Here the sentence is about position, not movement, so rado stays without -n.

Using la makes it the wheel, referring to a specific wheel that is known from context. If you said apud rado, it would sound more like next to a wheel or next to wheel-type meaning, which is less natural in many contexts.

So la rado points to a particular wheel.

Not completely. Esperanto word order is fairly flexible compared with English, because the grammar is marked clearly by endings and prepositions.

La pumpilo estas apud la rado is the most neutral, natural order. But other orders are possible for emphasis, such as:

• Apud la rado estas la pumpilo.

That still means essentially the same thing, though it may sound more literary or emphatic.

A rough pronunciation guide is:

lah poom-PEE-loh ESS-tahs ah-POOD lah RAH-doh

A few helpful points:

• u sounds like oo in food
• i sounds like ee in see
• a sounds like a in father
• stress usually falls on the second-to-last syllable

So:

• pumpilo → pum-PI-lo
• estas → ES-tas
• apud → a-PUD
• rado → RA-do

Yes. Esperanto marks plurals with -j.

Examples:

• La pumpilo estas apud la radoj. = The pump is next to the wheels.
• La pumpiloj estas apud la rado. = The pumps are next to the wheel.
• La pumpiloj estas apud la radoj. = The pumps are next to the wheels.

This regular plural system is one of the easiest parts of Esperanto grammar.

Yes, depending on context. Pumpilo just means pump as a device. In real use, the listener may understand it as a bicycle pump, air pump, or another kind of pump depending on the situation. Esperanto often relies on context the same way English does.

If you wanted to be more specific, you could add another word, but the basic sentence itself is perfectly normal.