Phonological change

The sounds we speak can change. They change over time. Sometimes two sounds join to become one. This is called a merger.

Other times, one sound splits into two. This makes a language grow. It can create new ways to talk.

Some sounds change in certain spots. In German, some sounds change at the end of a word. This can change how a word sounds.

In old Latin, an "s" sound could turn into an "r" sound. This happened when the sound was between two vowels.

Languages are always moving and shifting. It is fun to hear how words change!

The sounds in a language can change over time. This is called phonological change. It happens when a language makes a new system of sounds. Sometimes, old sound patterns disappear. Other times, new ones appear.

One way sounds change is through a merger. A merger happens when two different sounds become the same sound. In North American English, the vowel in "lot" and "palm" often sound the same. This is a merger. Another way is a split. A split is when one sound turns into two new sounds. This can make a language grow.

Sometimes, sounds change only in certain spots. This is a conditioned merger. In German, some sounds change at the end of a word. For example, a "d" sound might sound like a "t" at the end of a word. This creates a gap where the "d" sound is not used.

In old Latin, sounds changed in specific ways too. An "s" sound between two vowels sometimes turned into an "r" sound. This is called rhotacism. Other times, a stop sound would change to match a nasal sound nearby. These shifts show how languages are always moving and changing.

Languages are always moving and changing. One way they change is through phonological change. This happens when the sounds in a language shift. These shifts change how sounds are used. A language might develop a new system of sounds. Old sound patterns might disappear entirely. New patterns might also appear or move around. This change is different from simple pronunciation. Simple changes are called phonetic changes. A phonetic change might happen in specific spots. For example, Japanese vowels can change near nasal sounds. These small shifts do not change the whole system. They are just small tweaks to how sounds feel.

There are different ways these sounds reorganize. Henry M. Hoenigswald described these in 1965. One way is a merger. This is when two different sounds become one. This reduces the total number of sounds. Another way is a split. This is when one sound becomes two. This increases the number of sounds. A third way is a conditioned merger. This is also called a primary split. In this case, some sounds change but others stay the same. This creates a gap in where a sound is used.

History shows us these changes in action. In old Latin, a famous change happened. It was called rhotacism. An "s" sound between two vowels turned into an "r." For example, the word *gesō became gerō. This rule was very regular. However, new "s" sounds appeared later. They came from short vowels or new words. Another change happened in Middle English. The "d" sound after a stressed syllable changed. It became a "th" sound in words like mother.

We can see these rules in modern languages too. In German, sounds change at the end of words. A "d" sound often sounds like a "t" there. This happens in words like hand or gold. This creates a rule for how people speak. In North American English, we see mergers too. The vowel in lot and palm can sound identical. In England, father and farther often sound the same. This happens because of "R-dropping" in many dialects.

These changes help us understand how words grow. Sometimes a small sound shift leads to a big change. In Proto-Italic, an "s" sound became a "z" sound. This was a small change at first. Later, it merged with the "r" sound. This had a much larger effect on the language. In Indo-Iranian, sounds changed near front vowels. These sounds eventually became distinct new sounds. This shows how tiny shifts build new languages.

Phonological change is a fundamental process in historical linguistics. It describes any sound change that alters the distribution of phonemes within a language. A phoneme is a distinct unit of sound that helps create meaning. When phonological change occurs, a language develops a new system of oppositions among its sounds. This means old contrasts between sounds might disappear entirely. New contrasts might emerge, or existing ones might simply be rearranged. This process can drive changes in the entire phonological structure of a language. It is a way that the internal logic of speech evolves over time.

To understand this, we must distinguish between phonological and phonetic change. Phonetic change is a shift in how a sound is pronounced. This is often called allophonic or subphonemic change. In these cases, the total number of phonemes in the language does not change. For example, in Japanese, vowels may undergo devoicing or nasalization in specific environments. These are small adjustments to how a sound is physically produced. A famous example is the Great Vowel Shift in English. During this shift, nearly all English vowels changed their pronunciation. However, because the sounds remained in complementary distribution, it is considered a phonetic change rather than a phonological one.

Phonological change involves a deeper restructuring of the language system. One major process is rephonemicization. This occurs when the distribution of phonemes changes through addition or reorganization. In 1965, Henry M. Hoenigswald systematized a way to classify these historical sound laws. He identified three primary ways a sound law affects a system. The first is a conditioned merger, which he called a primary split. In this process, some instances of one phoneme become an existing phoneme. The total number of phonemes stays the same, but their distribution changes.

The second type is a phonemic split, or a secondary split. This happens when some instances of one phoneme become a brand-new phoneme. This process, known as phonemic differentiation, increases the total number of phonemes. The third type is an unconditioned merger. This is a form of phonemic reduction. In this case, all instances of two different phonemes become one single sound. This reduces the total number of phonemes in the language.

Conditioned mergers often create specific patterns and gaps. When a merger is conditioned, some instances of a sound change while others do not. This results in fewer words using the original sound and more words using the new one. It also creates a gap in the distribution of the original phoneme. In Middle English, the /d/ sound after stressed syllables followed by /r/ changed to /ð/. This turned words like *módor* into *mother*. This change was a conditioned merger because it only happened in specific environments.

We see similar patterns in the history of Latin and German. Latin experienced rhotacism, where an /s/ sound between vowels became an /r/. For instance, the Proto-Italic *gesō became the Latin *gerō*. German shows a conditioned merger through the devoicing of stops at the end of words. A /d/ sound often becomes a /t/ sound in words like *Hand* or *gold*. This creates a rule where /b/, /d/, and /g/ are never found in word-final positions. These rules allow linguists to use internal reconstruction to trace how words originally sounded.

Small phonetic shifts often serve as the raw ingredients for larger phonological innovations. In Proto-Italic, the intervocalic */s/ became *[z]. This was initially just a minor phonetic change. However, when *[z] later merged with */r/, it caused a massive shift in the system. Similarly, in Indo-Iranian, velar stops acquired different pronunciations before front vowels. When the vowels themselves later merged, these different pronunciations became distinct phonemes. This is known as the law of palatals. It shows how tiny, localized shifts eventually build the complex structures of modern languages.