Numbers Pronunciation: Why 'Thirteen' and 'Thirty' Sound the Same (And How to Fix It)

"Wait, did you say THIRteen or THIRty?" This question happens all the time! Numbers are used in every conversation—ages, prices, dates, addresses, phone numbers—and mispronouncing them can cause real confusion. Let's fix that.

The Teen vs. Ty Problem

The most confusing number pairs in English:

The Two Key Differences

1. STRESS POSITION

This is the most important difference!

• -teen numbers: Stress on TEEN → thirTEEN /θɜːrˈtiːn/
• -ty numbers: Stress on FIRST syllable → THIRty /ˈθɜːrti/

2. VOWEL LENGTH

• -teen: Long "ee" sound /iː/ → thir-TEEN
• -ty: Short "i" sound /i/ → thir-ty

Practice: Stress Patterns

Practice: Basic Numbers

Numbers 1-10

Teen Numbers (11-19)

Phone Numbers

In American English, phone numbers are usually said in groups:

Format: (XXX) XXX-XXXX Example: (555) 123-4567

• Say: "five five five, one two three, four five six seven"
• Or: "five fifty-five, one twenty-three, forty-five sixty-seven"

Key Points:

• Say digits individually OR in groups of two
• Zero can be said as "zero" or "oh"
• Group numbers naturally: 555 → "five five five" or "triple five"

Years

Years 1000-1999

Split into two parts:

Years 2000-2009

Say the full number:

Years 2010+

Two options:

Decimals and Money

Decimals

• 3.5 → "three point five"
• 2.75 → "two point seven five" (NOT "two point seventy-five")
• 0.5 → "zero point five" or "point five"

Money

• $5.99 → "five ninety-nine" or "five dollars and ninety-nine cents"
• $10.50 → "ten fifty" or "ten dollars and fifty cents"
• $100 → "a hundred dollars" or "one hundred dollars"

Addresses and Floors

Street Addresses

• 123 Main Street → "one twenty-three" or "one two three"
• 4567 Oak Avenue → "forty-five sixty-seven"

Floors

• 1st floor → "first floor"
• 2nd floor → "second floor"
• 13th floor → "thirteenth floor"
• 30th floor → "thirtieth floor"

Common Mistakes to Avoid

Mistake 1: Wrong Stress on Teen/Ty

Wrong: THIRteen (stress on first syllable) Right: thirTEEN (stress on second syllable) Wrong: thirTY (stress on second syllable) Right: THIRty (stress on first syllable)

Mistake 2: Same Vowel Length

Wrong: Making -teen and -ty sound the same Right: -teen has a LONG /iː/, -ty has a SHORT /i/

Mistake 3: Pronouncing Silent Letters

Wrong: "eight" as /eɪɡt/ (pronouncing the g) Right: "eight" as /eɪt/

Mistake 4: Wrong TH Sound

"Three," "thirteen," and "thirty" all start with TH /θ/:

Wrong: "tree," "tirteen," "tirty" Right: "three" /θriː/, "thirteen" /θɜːrˈtiːn/

Practice Sentences

I'm thirty-three years old, not thirteen!

The meeting is at 2:15 (two fifteen).

My phone number is 555-4321.

I was born in 1995 (nineteen ninety-five).

The total is $47.50 (forty-seven fifty).

There are fourteen people, not forty.

I live at 1850 Oak Street.

She'll arrive at 8:30 (eight thirty).

Quick Reference: Number Pronunciation

The "N" Trick for -teen vs. -ty

Here's a helpful hint: -teen ends with an "N" sound. -ty doesn't.

• thirteeN → ends with /n/
• thirty → ends with /i/

If people often misunderstand you, make the final N in -teen very clear!

Why This Matters

Getting numbers wrong can cause serious problems:

• Wrong meeting time (3:13 vs. 3:30)
• Wrong prices ($15 vs. $50)
• Wrong addresses (13th St vs. 30th St)
• Wrong phone numbers

Master number pronunciation and avoid costly misunderstandings!

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