I am delighted that my grandchildren have learnt the word digraph in the reception class in their primary schools. A digraph is a sequence of two letters that together represent a single sound. One English digraph is <th>. This digraph is, in fact, used to spell two different consonants:
- a voiceless consonant, as in the word written as <think>. In the International Phonetic Alphabet (IPA), the symbol for this sound is θ.
- a voiced consonant, as in the the word written as <this>. The IPA symbol for this sound is ð.
English words starting with ð
As far as I know, English words are free to start with the unvoiced consonant θ—though there are some restrictions on sequences of θ followed by another consonant. However, very few English words start with the voiced consonant /ð/. In fact, the only such words are:
- the definite article and some demonstratives
- a personal pronoun
- words denoting something far from the speaker
Article and demonstratives
The most common words starting with /ð/ are the definite article <the> and the demonstratives <this> and <that> and their plurals <these> and those>.
Also in this category is perhaps <thus> (meaning in this way).
This voiced consonant also appears in some personal pronouns:
- the 3rd person plural <they> and its inflected forms <them>, <their> and <theirs>
- the archaic 2nd person informal singular <thou> and its inflected forms <thee>, <thy> and < thine>
Far from the speaker
Some other words starting with this voiced consonant form one part of a set of three. For instance, <there> is one member of a set whose other members are <here> and <where>. In these sets, a word:
- starts with /h-/ to denote something near the speaker (a proximal form)
- starts with /th-/ to refer to something far from the speaker (a distal form)
- starts with /wh-/ to ask a question (an interrogative form)
The following table lists these forms:
Some of the words in this table also form compounds. The commonest is probably <therefore>. Some others include <therefrom>, <thereto>, <thereabout> (and the adverb <thereabouts>) and <thenceforth>. Many of these other forms are now archaic or legalistic.
Another word that falls into a similar pattern as those in the table is <then> (at that time). It has an interrogative counterpart <when> (at what time), but there is no ‘hen’ (to convey the meaning at this time = now).
The word <than> was originally the same form as <then> and was spelled the same way, but eventually came to be distinguished in both pronunciation and spelling.
Each category listed above is plausibly analysed as containing an element [th-] conveying the meaning ‘far from the speaker’. Similarly, words such as <here> and <where> are plausibly analysed as starting with an element pronounced as [h-] or [w-].
Linguists call such elements of meaning ‘morphemes’. Morphemes can be free—if they can appear alone—or bound if they can only appear as part of a word. So the elements [th-], [h-] and [w-] mentioned in the preceding paragraph are bound morphemes.
So, in summary, no English word can start with the voiced sound [ð] unless that sound is a bound morpheme meaning ‘far from the speaker’. Exceptionally, the bound morpheme means ‘near the speaker’ in two forms: <this> and <thus>.