Eu ponho uma rodela de limão no chá.

Ponho is the 1st person singular present form of the verb pôr, which means to put.

So:

• pôr = to put
• eu ponho = I put

This verb is irregular, so the form is not something fully predictable from the infinitive.

A few present-tense forms are:

• eu ponho = I put
• tu pões = you put
• ele/ela põe = he/she puts
• nós pomos = we put
• vocês/eles/elas põem = you/they put

Yes. In Portuguese, subject pronouns are often omitted when the verb form already makes the subject clear.

So both are natural:

• Eu ponho uma rodela de limão no chá.
• Ponho uma rodela de limão no chá.

Because ponho clearly means I put, eu is optional unless you want emphasis or contrast.

For example:

• Eu ponho limão, mas ele põe leite.
  = I put lemon, but he puts milk.

Rodela means a round slice, especially of something circular like lemon, onion, tomato, or cucumber.

So uma rodela de limão is:

• a lemon slice
• more literally, a round slice of lemon

This is a very natural word in Portuguese for food cut into circular slices.

Compare:

• rodela de limão = lemon slice
• fatia de limão = slice of lemon, but fatia is more general and often used for things like cake, bread, cheese, ham, etc.

In this sentence, rodela is the most idiomatic choice.

Because de limão here expresses what kind of slice it is, not a slice from a specific lemon already identified.

• uma rodela de limão = a slice of lemon
• uma rodela do limão = a slice of the lemon

So:

• de limão = lemon as a substance/type
• do limão = from the specific lemon

In most everyday contexts, when saying what something is made of or what type it is, Portuguese uses de:

• sumo de laranja = orange juice
• bolo de chocolate = chocolate cake
• rodela de limão = slice of lemon

No is a contraction of:

• em
  • o = no

So no chá literally means in the tea.

This is one of the very common Portuguese contractions:

• em + o = no
• em + a = na
• em + os = nos
• em + as = nas

Examples:

• no café = in the coffee
• na sopa = in the soup
• nos copos = in the glasses
• nas chávenas = in the cups

Portuguese uses definite articles more often than English does.

So no chá literally looks like in the tea, but in natural English it is often just in the tea or in my tea, depending on context.

Portuguese often prefers the article in places where English does not. That is very normal:

• Gosto de café. = I like coffee.
• Pus açúcar no café. = I put sugar in the coffee / in my coffee.

So don't try to match article use word for word with English.

You can also use colocar.

Both are possible:

• Eu ponho uma rodela de limão no chá.
• Eu coloco uma rodela de limão no chá.

The difference is mainly one of style and frequency:

• pôr = very common, everyday, basic verb for to put
• colocar = also common, sometimes slightly more formal or neutral

In casual speech, pôr is extremely natural.

It can mean either, depending on context.

Eu ponho uma rodela de limão no chá can mean:

• I put a slice of lemon in tea / I usually put...
  (habit, routine)
• I’m putting a slice of lemon in the tea
  (what I’m doing now, especially in conversation or explanation)

Portuguese often uses the simple present more broadly than English.

If you want to make the ongoing action very explicit, European Portuguese often uses:

• Estou a pôr uma rodela de limão no chá.
  = I am putting a slice of lemon in the tea.

In normal Portuguese, uma is the natural choice here.

• uma rodela de limão = a slice of lemon

Leaving out the article would sound incomplete or unnatural in most standard contexts.

Portuguese usually requires an article or determiner with singular countable nouns, just like English does:

• a slice
• uma rodela

So ponho uma rodela de limão no chá is the normal form.

The given order is the most neutral and natural:

• Eu ponho uma rodela de limão no chá.

But Portuguese does allow some flexibility, especially for emphasis.

For example:

• No chá, eu ponho uma rodela de limão.
  This emphasizes in the tea.
• Uma rodela de limão eu ponho no chá.
  Possible, but more marked and less neutral.

For a learner, the safest default is:

Subject + verb + object + place/complement

A broad European Portuguese pronunciation would be approximately:

eu PONH-u oo-muh ru-DEH-luh d’lee-MÃO nu SHAH

A few useful notes:

• eu often sounds like a quick eh-o / yo-like glide
• ponho: the nh sounds like the ny in canyon
• uma in European Portuguese is often reduced, not fully pronounced like in Brazilian Portuguese
• de limão often links smoothly, with de reduced
• chá has a sh sound at the start

If you want a rougher breakdown by word:

• Eu
• ponho = PON-yu / PONH-u
• uma = oo-muh (often reduced)
• rodela = ru-DEH-luh
• de limão = d’lee-MÃO
• no chá = nu SHAH

Chá is masculine.

That is why you get:

• o chá = the tea
• no chá = in the tea

Other examples:

• Este chá está quente. = This tea is hot.
• O chá tem limão. = The tea has lemon.

Yes. Depending on context, it can be understood generally or specifically.

It may refer to:

• a general habit: I put a slice of lemon in tea
• a repeated preference: I add lemon to my tea
• one specific action: I’m putting a slice of lemon in the tea

Portuguese often leaves this kind of distinction to context rather than marking it very explicitly.

Yes, this is a natural sentence in European Portuguese.

It sounds like normal everyday Portuguese. In real conversation, a speaker might also say:

• Ponho uma rodela de limão no chá.
• Costumo pôr uma rodela de limão no chá. = I usually put a slice of lemon in tea.
• Estou a pôr uma rodela de limão no chá. = I’m putting a slice of lemon in the tea.

But your original sentence is completely natural.