Affricates

How many consonants are in the word chew? One ch sound? A t and a sh sound? As it turns out, it's a little bit of both.

This sound is an example of an affricate: a hybrid consonant that consists of a stop and a fricative. Affrication is a manner of articulation that is present in a great number of languages and can distinguish the meaning of different words.

Affricate Sounds

An affricate sound is considered a hybrid consonant because it consists of two sounds.

Affricates are usually notated as a stop and fricative connected by an overhead tie (e.g. [t͡s]).

The two affricates that appear as phonemes in English, [t͡ʃ] and [d͡ʒ], are typically written as ch and j or g. Examples include the ch in child [ˈt͡ʃaɪ.əld] and both the j and dg in judge [d͡ʒʌd͡ʒ].

Affricates and Fricatives

While they contain fricatives, affricates are not equivalent to fricatives. An affricate shares properties of both a stop and a fricative.

You can see the difference between stops and fricatives by looking at a spectrogram. Spectrograms are helpful for visualizing the frequency range and amplitude (loudness) of a sound over time. The waveform also provides information about a sound's amplitude and other values. The image below includes a waveform at the top, a spectrogram in the middle, and annotations of the sounds at the bottom.

Fig. 1 - The affricate [t͡s] has the quick burst of air of the stop [t] and the sustained, turbulent airflow of the fricative [s].¹

A stop is a full closure of the vocal tract. The sound of a stop is the burst of air that occurs when the closure is released. These are the stages of a stop that are visible on a spectrogram.

• Closure: A white space represents silence.
• Burst: A sharp, vertical dark stripe appears as the closure is released.
• Following noise: Depending on the stop, this could look like a very brief fricative or the beginning of a brief vowel.

A fricative is a turbulent stream of air through a partial closure of the vocal tract. On a spectrogram, this is a "fuzzy," static-like stream of noise. Because they involve a continuous stream of air, fricatives can be sustained for a long time. This means that fricatives can take up a larger amount of horizontal space on a spectrogram than stops.

An affricate is a combination of a stop and a fricative; this is visible on a spectrogram. An affricate begins with the sharp, vertical dark stripe at the stop's burst. It takes on the static-like appearance of the fricative as soon as the stop is released. Because it ends with a fricative, an affricate can last longer and occupy more horizontal space on the spectrogram than a stop.

Affricate Manner of Articulation

Three factors characterize consonants: place, voice, and manner of articulation. Affricate (or affrication) is a manner of articulation, meaning that it defines the mechanism used to produce a consonant.

As for place and voicing:

• Affricates can occur in various places of articulation. The only constraint is that the stop and fricative must have roughly the same place of articulation.
• Affricates can be voiced or voiceless. The stop and fricative can't differ in voicing: If one is voiceless, the other must be voiceless too.

Examples of Affricates

Affricates come in several shapes and sizes, but these examples cover some common affricates.

The voiced [d͡ʒ] and voiceless [t͡ʃ] postalveolar affricates are the two affricate phonemes in English. You can see examples of [t͡ʃ] in cheer, bench, and nachos. Examples of [d͡ʒ] are in the words jump, budge, and badger.

The voiceless bilabial-labiodental affricate [p͡f] appears in German in words like Pferd (horse) and Pfennig (penny). Some English speakers use this sound as a derisive noise of frustration (Pf! I can't believe this.)

The voiceless alveolar lateral affricate [t͡ɬ] is an alveolar stop combined with a lateral fricative (a fricative in the L position). It appears in the Otali Cherokee language in words like Ꮭ [t͡ɬa], which means no.

What is the Meaning of Affricates?

One question still remains: how do affricates affect the meaning of words? If an affricate is just a stop combined with a fricative, is it at all different from a stop next to a fricative?

An affricate is distinct in meaning from a stop/fricative sequence. It can distinguish phrases like great shin and gray chin. If affricates can set these expressions apart, they must carry a unique acoustic signal that people can perceive.

To find an observable acoustic difference between a stop/fricative sequence and an affricate, look once again at the spectrogram. This spectrogram shows a speaker saying last shell with a stop/fricative sequence and less chill with an affricate.

Fig. 2 - The stop-fricative sequence in last shell is similar, but not exactly equal to, the affricate in less chill.¹

From this distance, it's clear that the [t ʃ] sequence in last shell is slightly longer than the [t͡ʃ] affricate in less chill. The difference in duration could help acoustically signal the difference between the sounds.

Fig. 3 - A brief decrease in amplitude divides the stop [t] from the fricative [ʃ] in the sequence.¹

Zooming in on the stop/fricative sequence, you can see a brief decrease in amplitude where [t] ends and [ʃ] begins. This "gap" doesn't seem characteristic of an affricate.

Fig. 4 - In the postalveolar affricate, the fricative noise begins immediately after the release of the closure.¹

Sure enough, zooming in on the affricate shows that this gap between [t] and [ʃ] is not present. Not only can we hear the difference between affricates and stop/fricative sequences; we can see it too!