Phonetic Assimilation

When we speak, we often change the ways we pronounce words. This tends to happen a lot if we speak fast. But do you know why this happens? This relates to the topic we are focusing on today - phonetic assimilation.

We will explore the definition of phonetic assimilation, the different types, and some examples of each. We will also consider the differences between assimilation, elision, and epenthesis - as it is easy to get these three processes mixed up!

Fig. 1 - Assimilation occurs in our speech when we slightly change the way we pronounce words.

Assimilation in phonetics

Assimilation in phonetics is the process in which a sound is influenced by and becomes similar to a surrounding sound. This means that the pronunciation can vary depending on the order of certain letters in different words. This is usually done to ease pronunciation, especially when words are said quickly.

Why is this?

This happens because both the /d/ and /b/ sounds have different places of articulation, meaning they are pronounced using different parts of the mouth:

• /d/ is pronounced by tapping the tongue against the alveolar ridge (the part right behind your upper teeth).

• /b/ is bilabial, meaning it is pronounced by placing both of your lips together. This makes it difficult to pronounce both of these letters sequentially, so the /d/ gets dropped.

The /n/ sound is also pronounced by tapping the tongue against the alveolar ridge, but, because it comes before the bilabial consonant /b/, it is labialised instead. This means that the /n/ sound turns into an /m/ sound. This makes it easier to pronounce the /m/ and /b/ sequentially, as they are both pronounced using the same parts of the mouth (the lips).

Other examples of words where this process occurs are sandbox, standby, windbreaker, sandwich etc.

What are the assimilation phonetics rules?

Assimilation in phonetics can be described as having a certain set of rules. These rules determine how sounds assimilate to others depending on what's surrounding them. For example a sound being changed because of what precedes it such as the 's' in 'bags' being changed to a voiced 'z' sound. These assimilation 'rules' determine the different types of assimilation in phonetics. We'll have a look at these now.

Types of assimilation in phonetics

There are different types of assimilation depending on which sounds are altered. A sound can either be influenced by the sound that comes before it or after it. The types are as follows:

• Progressive (before)
• Regressive (after)

Let's look at these in more detail.

Progressive assimilation

This refers to when a sound is influenced by the sound that comes before it.

Regressive assimilation

This refers to when a sound is influenced by the sound that comes after it.

What are the degrees of assimilation?

The types of phonetic assimilation mentioned above can further be split into two degrees of assimilation: total and partial.

Total assimilation

This refers to when the sound affected by the assimilation becomes the same as the sound that causes the assimilation. You can notice this within words or across sentences.

For example, let's take the phrase 'this shoe'. In fast speech, the /s/ sound at the end of 'this' is affected by the /ʃ/ (sh sound) at the beginning of 'shoe' and changes to the /ʃ/ sound.

Partial assimilation

This refers to when the sound affected by the assimilation becomes similar to the sound that causes the assimilation but does not change completely.

For example, let's take the phrase 'sit back'. In fast speech, the /t/ sound is influenced by the following /b/ sound and changes to become a /p/ sound:

/p/ is similar to a /b/ as they share the same place of articulation - both sounds are made by placing your lips together and pushing air out. But, they are not entirely the same, so this is only partial assimilation.

Phonetic assimilation examples

Below are some examples of phonetic assimilation:

Assimilation and elision in phonetics

It is easy to mix up elision and assimilation as they often occur simultaneously, and both are processes that change the pronunciation of words.

Elision refers to when consonants are omitted from a word/phrase. This is usually done to make words or phrases easier to pronounce in fast speech. It helps the utterance flow more naturally.

Epenthesis vs. assimilation in phonetics

This refers to when extra sounds are added to a word. This does not change the spelling of the word, only the pronunciation.

Assimilation and accommodation in phonetics

The terms assimilation and accommodation are both often used in phonetics when we talk about sound change. These are not interchangeable terms though; they relate to different types of sound change.

Assimilation is when a sound change is influenced by and becomes similar to its surrounding speech sounds.

Accommodation is when people's speech sounds change depending on who they're talking to. For example, if you're trying to make someone feel more comfortable or gain social approval, you'll slightly alter how you speak to accommodate the speech of your interlocutor. You can also create distance from the other person by emphasising linguistic differences and speaking differently to them.

Both assimilation and accommodation are most often subconscious sound changes.