View source for Consonant phonemes /θ/ and /ð/ in spelling

The English spelling <th> stands for two different sounds: [[th phonemes| the voiceless /ɵ/ and voiced /ð/]].  “Voiced” means you feel that vibration in the throat, from the vocal cords vibrating.  We will look at some hints to help you know how to pronounce <th>.  There are no absolute rules that can tell you to pronounce it as /θ/ or /ð/, but there are some very helpful guidelines. In this article, slash marks indicate phonemes, e.g., /θ/, /ð/, while angled brackets like <th> indicate letters or spellings. 


==Introduction== 
The English diagraph <th> represents two different phonemes in English: the voiceless dental fricative /θ/ as in "thin" and the voiced dental fricative /ð/ as in "this." Both sounds pose challenges for ESL/EFL learners, whose first languages probably lack these sounds, as both sounds are relatively uncommon throughout the world's languages. English spelling further complicates learning, since it does not distinguish the voiced and voiceless sounds. Here, slash marks like /θ/ and /ð/ denote phonemes, while angled brackets like <th> denote letters or spelling.
* See [[th phonemes| <th> phonemes]] for an introduction to these sounds. 

The voiced /ð/ sound tends to occur in function words (minor grammatical words like articles, determiners, and such, so a <th> spelling in such words is most often /ð/. This includes some words that are not used in modern English (marked with asterisks below). 
the, this, that, these, those, they, than, there, therefore, thereupon, though, although, then, hither*, thither*, whither*,  thee*, thy*, thou*, thyself*	

A few exceptions exist to these voiced /ð/ patterns<ref>Most ''-thy'' words are pronounced with /θ/, but in a few words it is pronounced with /ð/, namely: ''worthy, smoothy/smoothie.'' Some -er words are not from Old English and are pronounced /θ/, e.g., ''ether, Luther, panther, zither.'' Also note these “exceptions”:  ''smooth'' /ð/ (a spelling irregularity); and names of foreign origin where <th> is pronounced /t/: ''Esther, Mathilda, Thai, Thailand, Thames, Thomas''.</ref>. Most other content words (nouns, verbs, adjectives, adverbs) with <th> are pronounced with /θ/. Most likely, then, when you encounter an unfamiliar word with <th>, it will be /θ/.	 


==Basic patterns==
The most basic patterns for learners are the following:
# Function word pattern
# Old English suffix pattern
# Greek / Anglo-Saxon content word patterns (or the Elsewhere Principle)

===Function word pattern: <th> in function words = /ð/===
Function words are minor words (besides content words — nouns, adjectives, adverbs, and verbs); function words include prepositions, conjunctions, particles, pronouns, pro-forms (there), articles, etc.  The <th> in function words is usually at the beginning of the word, and is often pronounced /ð/ (but not always).
{| class="wikitable"
|- 
| articles || the 
|-
| pronouns, pro-forms || this, that, these, those, they, than, there
|-
|prep., conj.  ||than, therefore, thereupon, though, although, then
|}

Notes:
# The <th> of the following function words is /θ/ because they are compounded from ''thing'': ''anything, something, nothing, everything.'' 
# The <th> in ''through'' is pronounced /θ/. The preposition ''with'' is usually /wɪθ/ in North American English and other dialects, but /wɪð/ in some New England and British dialects.   	


===Old English (Anglo-Saxon) suffix pattern: <th> before Old English endings = /ð/===
The <th> before some Old English (Anglo-Saxon) suffixes and word endings is pronounced /ð/, in particular: 
* -e, -er, -ern, -en, -ing<small> (noun)</small>
 
The ''-e'' often creates verbs from nouns. In some cases we can see the original base word which has /θ/, but adding a suffix changes it to /ð/, but sometimes the original base word has disappeared from English. This ''-ing'' is a general noun suffix as in ''building'', not the verb ending. 

{| class="wikitable"
! θ   !!   →  ð !! !!  θ   !! → ð
|-
| bath	<br>
breath 	<br>
teeth 	<br>
sooth	
| bathe	<br>
breathe	<br>
teethe	<br>
soothe
| &nbsp;&nbsp; 
| cloth <br>
worth	<br>
north	<br>
south	<br>
heath	 
| clothing, clothier <br>
worthy<br>
northern, norther<br>
southern<br>
heather
|}

The same is true of other Old English words that were derived in a similar way, but have since undergone spelling changes that obscured this process, such as ''fathom'' /fæðəm/ and ''smooth'' /smu:ð/.
 
Some words from Old English with /ð/ + suffix: The voiced /ð/ also occurs in words with certain endings, including Old English endings, such as words formed by adding ''-e'' to nouns to turn them into verbs. In the following table, asterisks (*) indicate older,rarer, or obsolete words. 

{| class="wikitable" 
! ending !! examples 
|-
| -e
| bathe, blithe, breathe, clothe, lathe, loathe, scythe, seethe, soothe, teethe, tithe , mouth(e), tithe, wreathe, writhe 
|- 
| -er
| another, bather, blithering, bother, breather, brother, dither, father, farther, further, gather, heather, hither*, leather, mother, nether*, neither, norther, northerly, other, rather, slither, smother, southerly, tether, thither*, together, weather, whether, whither*, wither, wuther*, wuthering*; <br>
also ''-ier:'' clothier  
|-
| -ern
| northern, southern 
|-
| -en
| brethren*, heathen 
|-
| -ie, -ee
| smoothie, couthie*, smoothee, prithee* 
|-
| -ing <small>(nouns)</small> 
| clothing, farthing*, loathing, sheathing
|}

Also, a few other Old English words: 
# Most adjectives formed with ''-y'' are pronounced with /θ/, except for:
#* worthy /wɔrði/, unworthy, trustworthy 
# adjectives in ''-er, -est'' from Old English words like those forms above, e.g.,   
#*farthest, furthest, smoothest, worthiest

Notes.
# When adding other suffixes, such as verbal ''-ing,'' the pronunciation of the base word is retained in the new word: 
#* /ð/: breathe → breathing, breathed
#* /θ/: sleuth → to sleuth, sleuthing, sleuthed
# Words with the verbal suffix ''-then'' (to create verbs from adjectives) have /θ/, such as ''strengthen, lengthen.''  


===Greek / Anglo-Saxon content word patterns (Elsewhere Principle)===
Except for some unusual patterns in the next section, most <th> words in English that are content words (nouns, verbs, adjectives, adverbs) are from Greek, or from Anglo-Saxon (Old English) or medieval English, and are pronounced as /θ/. That is, unless the above conditions apply (function word, AS ending), the <th> elsewhere is usually /θ/.

For older English words, the <th> as voiceless /θ/ is usually found in initial (beginning of word) or final (end of word), which are naturally voiceless positions<ref>In Anglo-Saxon, the <th> sound was voiced in invervocalic (between vowels) or medial (middle of word or syllable) positions, and was unvoiced in word-initial and word-final positions, as it is easier for the glottis to vibrate medially and to not vibrate initially or finally. This voicing rule applied regardless of whether the Anglo-Saxon words were spelled with the old letters thorn <þ> or thagaz <ð>.</ref>. Most academic or technical words in English with <th> are from Greek, so for new academic words, one can guess that such words are pronounced with /θ/.
;Old English (AS) / medieval English: Arthur, birth, booth, broth,  earth, hearth, mouth, north, northwest, thank, thatch, through, Thursday, thud, throne, thousand, three, tooth, worth, ... 

;Greek: athletic, dysthymia, isotherm, lethal, metathesis, panthalassic, theocratic, thermos, therapist, thesis, thiamine, thyroid, ... 

Note: Words with ''-or'' like author are usually from Latin, where again <th> = /θ/.


===Other languages, and unusual or exceptional patterns: <th> = /ð, θ, t/ ===
The following patterns are for more advanced learners. These are (1) <th> words that come from other languages, (2) a few <th> words from Greek or via Greek, where a following /m/ makes the <th> voiced, or (3) a few other quirks as noted above. 

====Other words with /ð/====
* fathom, smooth 
These and a few other words have [ð], as noted above, due to Old English origins or the <thm> patterns above. The word smooth is a spelling irregularity; it came from an Old English ending (smothe/smoothe), with the final -e being dropped later.

====Non-Anglo-Saxon ''-ther'' = /θ/====
Some words have similar spellings as the Old English endings, but are not from Old English. They happen to have similar spellings, but come from other languages such as Greek and German, and these words are pronounced with /θ/: 
* anther, ether, panther, zither, Luther<ref>Actually, German does not have the /θ/ sound; ''Luther'' is pronounced more like /lutɜ/ in German, while the pronunciation of his name is Anglicized by English speakers who do not know German to /luθɜ(r)/.</ref> 

====<th> =  /t/====
In these proper names and words (which come from other languages), the <th> is pronounced as /t/, not as /θ/ or /ð/: 
* Esther (from Persian), Thomas (from Aramaic), * Mathilda (or Matilda; from Gothic) 
* Thai, Thailand (from Thai)
* Thames (from Celtic)
* thyme (from Greek via Latin and Old French, apparently with French alteration of /θ/ to /t/, as French lacks the /θ/ sound)
* Neanderthal (from German)<ref>However, some English speakers Anglicize the pronunciation to /θ/ in ''Neanderthal.''</ref>; Luther (original German pronunciation) 

====<th> + <y> =  /θ/ in adjectives====
Adding the adjective suffix <-y> generally does not change the sound of <th>; it generally remains /θ/.
* froth - frothy 		
* health - healthy  	
* pith – pithy

====Greek / Greceanized ''-thm'' spelling pattern====
In the following words, the <th> is voiced by the adjacent /m/. These are mostly from Greek, except ''algorithm'' (which came from Persian, but came into Greek and was adapted to the Greek spelling pattern). 
* algorithm algorithmic antilogarithm antiarrhythmic arrhythmic biorhythm dysrhythmic eurhythmic eurythmic isthmic logarithm polyrhythm rhythm logarithm logarithmic polyrhythmic rhythmic

==Pattern summary==
When you encounter words with the <th> spelling, you can put them through the following test to determine its pronunciation:  
{| class="wikitable"
|-
| 1. Function word || Is it a function word?  If so, then probably voiced /ð/. 
|-
| 2. Old English ending || Is it an Old English ending?  If so, then voiced /ð/.  
|-
| 3. Exceptional pattern || A small number of unusual words and patterns could mean /ð/, /θ/, or /t/.
|-
| 4. Elsewhere rule || You can probably assume it’s the voiceless /θ/ from Greek (academic words) or older non-academic English words.  
|}



==See also==
<references/>

===Other pages===
[[Portal:Phonology]]

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[[Category:Consonants]] [[Category:Phonology]] [[Category:Morphophonology]] [[Category:Morphology]]