Teaching Segments #1: English /ð, d/ - Part 1: Exploring phonemic and allophonic differences

I have been teaching general English and English "for international exams" (OMG, I do have a grudge for that) for over ten years now, and I started teaching phonetics at College in 2006. I wouldn't say I'm tooo experienced, but I would say that one of the features I have "corrected" and "systematised" the most among my Spanish-speaking students, is the contrast /ð/,/d/.

Some basic, general remarks for General British /ð/,/d/.:

• General British (GB) has a phonemic contrast between /ð/,/d/. This means that if we apply the process of commutation, through which we change one phoneme of a word for another, then we will have another acceptable English word, creating a minimal pair: "they"/"day", /ðeɪ//deɪ/. This proves that these two are phonemes of English.
• /ð/,/d/ are represented by different spellings in GB as well: /ð/ is generally, if not always, "th", /d/ is unproblematically spelled with "d" or "dd".
• /ð/,/d/ are clearly different in terms of place and manner of articulation, but share the same voice: both sounds are produced with vocal fold vibration. Curious to see what that looks like? Try this video. 
• /d/ is an alveolar sound in terms of its place of articulation, i.e., the tip and blade of the tongue are in contact with the alveolar ridge:

Image credit: http://www.study-languages-online.com/images/sounds/sound-d.gif

•  As far as manner of articulation is concerned, it is a plosive sound, which means that it is produced in three stages: a closure stage, whereby you put your articulators in firm contact, a compression stage in which the air is kept "hostage" behind the closure, and a sudden, "explosive" release (If English is your L1, or you have already "acquired" this sound, you can try this in slow motion). This is generally represented with parametric diagrams like the one below (adapted from Ortiz Lira & Finch, 1982):

• /ð/ is a dental sound, as the tongue articulates with the teeth (Mott 2012:134 states that in English it is generally "dental rather than interdental", though it is more useful in pedagogical terms to go for an interdental articulation, in my humble opinion!). This dental articulation is made fun of in the famous cartoon from the book How to be British:

Regarding manner of articulation, /ð/ is a fricative sound, and instead of presenting any degree of closure, there is a narrow opening between the articulators which creates friction (i.e, "turbulence"):

Fricatives. (Diagram adapted from Ortiz Lira & Finch, 1982)

You can watch an animation of their articulation in the University of Iowa site.

 (Digression alert!) Check out this MRI of a person singing a rap song (It's awesome!). It's great to see what goes on in your mouth cavity as you talk in real time!

What do we know about "d"-related sounds in my Riverplate variety of Spanish?

• We have got only one phoneme, /d/. As García Jurado and Arenas (2005:99) explain, it is an (post)dental plosive ("oclusiva apicodental")

Image credit: University of Iowa-Phonetics http://www.uiowa.edu/~acadtech/phonetics/spanish/frameset.html

Now. The interesting thing about our Spanish/d/ is that it has two main allophones, that is, two main variants. If you listen to my rendering of the word "dedo" ("finger"), you may notice two different productions of the sound (I'm still at odds with PRAAT's text grid feature...sorry!): 

1. This goes to say that my Riverplate Spanish /d/ has two "versions": a dental plosive [d̪]; and a dental fricative (even approximant at times for some speakers!) [ð], which appears in intervocalic position, and sometimes after nasals as well: ['d̪eðo].

(Not after nasals, my colleague Zabala corrects me. In my articulation it is true it is not a fricative, though I recall having read this somewhere. I'll trace the source)

So the RS learners of General British finds themselves entangled in what is called an allophonic split (Lado, 1957), that is, two allophones of their L1 which are two separate phonemes in their L2 (a "phonemization of allophonic variation", Moore, 2013).

Now. Is it only this split that makes /d, ð/ difficult for Argentinian learners of English? After all, how truly aware are we of the sounds we use in our language, as a general rule?

The answer to this question can to a certain extent, be found in a Contrastive Analysis (Weinreich, 1953), like the one carried out just now. But there may be other psycholinguistic factors also operating which may affect the mispronounciation of /d, ð/ among my learners . Part 2 will explore these phonological processes in more detail, explain some of the most common problems RS learners of English face regarding these sounds, and present some tips and tricks for classroom use.