It's usually pretty difficult for my Japanese students to make the  distinction between "thirteen" and "thirty", even at the lower intermediate  level. Often, when they say a number like 16, it sounds like "sixty", and when  you repeat the number in English to confirm it ("Did you say sixty?"), they say  "yes, 16." This page talks about using Captur Paddles with words that sound similar.

The problem is more a matter of incorrect stress patterns than actual pronunciation problems. Even after practicing in class, many sound better with the 'teen numbers, but still put too much final stress on thirty, forty, etc.

Traditional remedy

The traditional approach seems to work, at least in the short-term, and it gives them a strategy for the future. It starts with writing the words on the board and underlining or circling the stressed syllable. Have the students repeat after you.

• 16: sixteen
• 60: sixty

However, as mentioned above, many students will still place too much stress on the final syllable of 60. They'll say something akin to a cross between "sixteen" and "sixty". I demonstrate how to really take it down a notch by saying the first syllable loudly, and whispering the second one. I write it on the board as a very large 6 and a small "t" or "d".

Letting them try it out

Here's an activity that puts students together in pairs. One of them produces the number (16 or 60) and the other uses the Captur paddles to indicate which one was said.

Have the students face each other, if possible. Tell them that the student on the right is "A" and the student on the left is "B". Draw a table like this on the board:

So, to start, student "A" chooses either 13 or 30, and says it to student "B". Student "B" uses her Captur paddle to indicate which number she thinks that "A" has said. The students do this a total of 3 times. Then, they move on to the next row, switching roles.

Embed the numbers

Isolated numbers are generally easier than numbers that are embedded into a sentence. This is true for both the speaker and the listener. A variation on the above exercise is to have the student put the numbers in context. You could write some example sentences on the board, or you could tell the students to come up with their own sentences. For example:

• Mary turned 13 last month.
• Joe turned 30 yesterday.
• I have 13 cousins.

Listening to the teacher

Next, go through some listening activities with the students. They listen to you as you either say the numbers in isolation or within a sentence, and all of the students use their Captur paddles to show which number they heard.