The <th> sounds, while prominent in English, are absent in many other languages. Many non-native learners have difficulty pronouncing the sounds, even once they have a solid grasp on the English language (in other words, the mispronunciation of the sounds are a feature of many foreign accents). To help learners sound more natural, here are some ways you can address pronunciation at beginner stages.
First, let’s clarify the two sounds:
/θ/ is the soft
used in words like with, throw, fourth, and thing.
/ð/ is the hard
used in words like the, mother, that, and weather.
The difference between soft (unvoiced) and hard (unvoiced) is a vibration in your throat. Hold your hand to your neck as you make soft sounds like /θ/, /f/, and /s/, then see how it feels different as you make the hard sounds /ð/, /v/, and /z/.
Okay, let’s look at how to address with your students.
Demonstrate using the sounds to your students, and show them what your mouth looks like when you do it. In particular, call attention to how the tongue reaches out a bit and rests against your top teeth. The /θ/ sound is made simply by breathing out through your mouth when your tongue is in this position (and again, the /ð/ sound is made by adding the vibrations in your throat).
For many students, making those sounds on their own is not to difficult. But producing those sounds along with other – as one does in words and sentences – is another matter. Young students will have an easier time producing the sound, but they may need to be reminded of it when speaking (otherwise they’re liable to subconsciously default to a similar sound native to their first language).
My favorite way of reminding students of the sound they’re supposed to produce is by sticking my tongue out far farther than is reasonable. For younger children, making that funny face is comical, which both lightens the mood in the room and helps them to remember it later.
You might argue that doing this teaches poor form, as won’t sound quite right when your tongue is as far out as you can stick it. But don’t worry about it. When you’re speaking whole words or phrases, you don’t have time to stick your tongue out that far after the previous sound and before the next. When speaking at a normal pace, students will shorten how far they stick out the tongue so that the tip is just barely past the teeth – right where it should be.
Going forward, whenever my student mispronounce a word with <th>, I ask them to try again, then stick my tongue out at them.
Contrast Words with Similar Sounds
I say ‘contrast’, but we’re not getting analytical here, especially with young learners. Have student produce to different (but similar) sounds over and over, and they’ll start to figure out the difference, perhaps subconsciously.
Depending on the features of their native language, students may substitute /f/, /s/, or /t/ for /θ/ and substitute /v/, /z/, or /d/ for /ð/. Try taking words that they know and put them into groups. As you and they pronounce the words, stress the sounds as well as the sounds they tend to be be substituted with.
For example, if your students are likely to use /f/ and /v/, you might consider words like these:
Alternately, if your students tend to use /s/ and /z/ instead of the <th> sounds, these words might help:
These are just examples; it’s best to use words that your students already know well or have learned recently.
Say all the words in one category, perhaps a couple of times, stressing the key sound. Only move on to the next category once they’ve correctly pronounced the words. When it gets to the point at which most students are consistently making the right sounds, then try switching up the order: use one word from one category, then another word from another category, then go back and forth or jump to the third and fourth category.
You can even make a game of this once the students are more comfortable with the sounds. Bring two or three students to the front and point to a word you’ve written on the board. The first student to correctly pronounce the words scores a point for their team. Let them return to their seats and bring up another two or three students for the next round.
As with many things, even after students get the hang of this during a lesson, some of them may revert to mispronunciations the next day. After you put enough focus on this in order for the students to understand what you expect of this, you can revisit this in different ways as a five-minute activity in later lessons.
It may take a long time before they pronounce <th> correctly, but addressing this at an early stage will set them on the right path to lessening their accent.