Good and bad words to speak English well

When I started teaching English after many years in corporate finance, one thing surprised me. My students often had excellent grammar and a wide vocabulary, yet they sometimes sounded rude, cold or strange to native speakers. The problem was not their level. It was word choice. A single word, such as "must" instead of "could", or "fat" instead of "big", can change how people see you. In English, politeness lives inside small words.

In this article I share the "good words" I teach every student, the ones that make English sound warm and professional, and the "bad words" that are better avoided, from overused fillers to genuinely offensive language. I will also explain why, because understanding the culture behind the words is what really helps you remember them.

Part 1: Good words that make you sound polite and professional

1. Please and thank you, many times

English speakers, especially in Canada and the United Kingdom, say "please" and "thank you" constantly: to the bus driver, to the waiter, to colleagues, to family. Spanish speakers sometimes find this excessive, but omitting them in English can sound abrupt. A good rule: if you ask for something, add "please"; if you receive something, say "thank you" or "thanks".

2. Could, would and might: the magic softeners

Direct imperatives are common in Spanish ("Pásame el informe"), but in English they can sound like orders. Use modal verbs to soften requests:

• "Could you send me the report, please?"
• "Would you mind closing the door?"
• "Would it be possible to move the meeting to Friday?"
• "It might be a good idea to check the numbers again."

3. I'm afraid, unfortunately and I'm sorry

These words soften bad news or disagreement:

• "I'm afraid I can't attend the meeting."
• "Unfortunately, the product is out of stock."
• "I'm sorry, but I don't agree with that point."

4. Words that show respect for other opinions

• "I see your point, but…"
• "That's a good idea. Another option could be…"
• "I understand what you mean. However…"
• "In my opinion…" / "From my perspective…"

Read more in negotiating and disagreeing politely.

5. Positive and encouraging words

English speakers use a lot of positive feedback. Words such as great, excellent, well done, good job, I appreciate it, that's really helpful and I love that idea build good relationships at work and in life. In my classes I use them all the time, because I believe students learn better when they feel confident.

6. Precise verbs instead of general ones

Professional English becomes stronger when you replace general verbs with precise ones:

7. Hedging words for careful statements

In business and academic English, it is wise not to sound too absolute. Words such as probably, likely, it seems, in general, tend to and approximately make your statements more accurate and more diplomatic: "Sales are likely to increase next quarter" sounds more professional than "Sales will increase."

8. Small talk words

Friendly expressions open conversations: "How was your weekend?", "How's it going?", "Have a nice day!", "Enjoy your meal!", "Take care!". They seem simple, but they create connection, and connection is what makes people want to work with you. Read small talk in English.

Part 2: Bad words and expressions to avoid

1. Commands without softeners

"Send me the file." "Call me tomorrow." "Explain this." In English, these can sound rude, even if you did not intend it. Add "please", or use "Could you…?" The difference in how people react is enormous.

2. "You must" and "you have to" with clients or superiors

"You must sign the contract today" sounds like a threat. Prefer "We would need your signature by today, if possible" or "Could you sign the contract today?".

3. "I want…" in requests

In a shop or restaurant, "I want a coffee" sounds childish or demanding. Say "I'd like a coffee, please" or "Could I have a coffee, please?".

4. Overused fillers

Fillers are normal in every language, but too many make you sound unsure or unprofessional. Watch out for:

• "Like" repeated in every sentence: "It was, like, really, like, difficult."
• "You know" at the end of every idea.
• "Basically" and "actually" used without meaning.
• "Ehhh" and "emmm": in English, prefer a short silence or "Let me think…".

5. Swear words and vulgar language

Students often learn swear words from films, series and music, and they hear native speakers use them casually. But using them is risky for learners, because you may not know how strong a word is in a particular context. A word that seems light in a film can be very offensive in an office, in front of an older person or in another English-speaking country. My advice is simple: understand them when you hear them, but do not use them, especially at work, in interviews, with clients or in writing. If you need to express frustration, use mild alternatives such as "Oh no!", "What a pity!", "That's annoying" or "Oh dear".

6. Words about people's bodies, age or appearance

In some cultures, it is normal to comment on someone's weight or appearance, even affectionately. In most English-speaking cultures, it is not. Avoid words such as fat, old or comments like "You look tired" or "You've put on weight". If you want to compliment, focus on choices, not bodies: "I love your jacket" or "That colour suits you".

7. Outdated or offensive labels

Language evolves, and some words that were common decades ago are now considered offensive when referring to people's origin, disability, gender or other characteristics. The safest approach is to use the terms people use for themselves, prefer "person-first" or neutral expressions, and avoid nicknames based on appearance or origin. When in doubt, ask your teacher or simply describe people by their role or name.

8. False friends that can embarrass you

False friends are words that look similar in Spanish and English but mean something different. Some can cause funny or embarrassing situations:

Read the full list in false friends between Spanish and English.

9. Very informal words in professional contexts

Words like gonna, wanna, yeah, nope, stuff, guys and abbreviations such as u or pls are fine with friends, but in professional emails, presentations and interviews prefer going to, want to, yes, no, things or materials, everyone or team, and complete words.

10. Absolute words that create conflict

Always, never, impossible, wrong, your fault. In disagreements, these words make people defensive. Compare "You never send the report on time" with "The report has arrived late a few times. How can we fix that?". The second version solves the problem; the first starts a fight.

Register: the secret behind good and bad words

Linguists call it "register": the level of formality you choose according to the situation. The same idea can be expressed in many registers:

• Very informal: "Gimme a sec."
• Informal: "Just a second."
• Neutral: "One moment, please."
• Formal: "Could you bear with me for a moment, please?"

Good English is not always formal English. It is English that matches the situation. With friends, "Gimme a sec" is perfect; in a client meeting, it is not. Learning to move between registers is one of the signs of an advanced speaker.

Good words for emails and messages

Written English needs even more care than spoken English, because the reader cannot hear your friendly tone or see your smile. These words and phrases make emails warm and professional:

• Openings: "I hope you're well." / "Thank you for your message." / "I hope you had a good weekend."
• Requests: "Could you please…?" / "I would appreciate it if you could…" / "When you have a moment, could you…?"
• Bad news: "Unfortunately…" / "I'm afraid that…" / "I regret to inform you that…" (very formal)
• Follow-up: "Just a quick reminder about…" / "I wanted to follow up on…"
• Closings: "Thank you in advance." / "Please let me know if you have any questions." / "Best regards," / "Kind regards,"

And these are better avoided in professional writing: messages written entirely in CAPITAL LETTERS (they look like shouting), long chains of exclamation marks, "ASAP" in a demanding tone, and "As I said in my previous email…", which can sound impatient. Prefer "As mentioned earlier…" or simply repeat the information kindly.

Good words in different English-speaking cultures

Even among native speakers, word choice varies. In Canada, where I grew up after being born in Sweden, people apologise a lot: "Sorry!" can mean "excuse me", "I didn't hear you" or even "you stepped on my foot". In the United Kingdom, understatement is common: "not bad" can mean "very good", and "quite interesting" can mean "not interesting at all". In the United States, people tend to be more enthusiastic: "awesome" and "amazing" appear everywhere. Knowing these tendencies helps you understand what people really mean and choose words that fit your audience.

How to practise good word choice

1. Notice: when you watch series or listen to podcasts, pay attention to how characters ask for things and disagree.
2. Collect: keep a notebook of polite phrases you like.
3. Transform: take direct sentences and rewrite them politely.
4. Role-play: practise real situations with a teacher, such as complaining in a hotel or disagreeing in a meeting.
5. Ask for feedback: ask your teacher or colleagues to tell you if something sounds too direct.

A quick exercise

Rewrite these sentences in a more polite way. Possible answers are below.

1. Give me the menu.
2. You are wrong.
3. I want to speak with the manager.
4. Send the documents now.
5. Repeat.

Possible answers: 1) "Could I see the menu, please?" 2) "I see it a little differently." 3) "Would it be possible to speak with the manager, please?" 4) "Could you send the documents as soon as possible, please?" 5) "Sorry, could you repeat that, please?"

Why this matters to me

I have lived and taught in many cultures, from Egypt to Malaysia, Uruguay and Colombia. Every culture has its own rules of politeness, and none is better than the others. But when you speak English with international colleagues, clients or new friends, knowing the English rules of politeness helps people see the real you: kind, competent and respectful. That is what I want for every student. In Colombia, I have learned beautiful polite expressions too; read the Colombian Spanish words I love.

Frequently asked questions

Why do English speakers say "please" and "thank you" so often?

Because politeness in English is expressed largely through small words and indirect forms. Omitting them can make a request sound like an order.

Should I learn swear words in English?

It helps to understand them when you hear them, but it is better not to use them, because their strength changes with context and country.

What is the most polite way to ask for something in English?

Use "Could you…, please?" or "Would you mind…?". For very formal situations: "Would it be possible to…?"

What are false friends?

Words that look similar in two languages but have different meanings, such as "embarrassed" (avergonzado) and "embarazada" (pregnant).

Is informal English bad?

No. Informal English is perfect with friends. The key is to match your register to the situation.