Yesterday I posted on my social media about the spelling of the word <broad>. I just introduced the <oa> grapheme to my 5-year-old. The digraph <oa> typically spells the phone [oʊ] as in <oak>, <boat>, <soap>, <road>, and <hoax>. So why does the <broad> spell [bɹɔd] (or [bɹɑd] in Englishes with the cot-caught merger)?
The primary function of English spelling is to represent meaning. Structured Word Inquiry (SWI) is a means by which to study spelling. One can use SWI to investigate spelling by asking four questions:
- What does a word mean?
- How is the word built?
- What are morphological and etymological relatives of the word?
- What are the sounds that matter?
The questions are to be investigated in order.
Question 1: What does <broad> mean? <broad> means “wide.”
Question 2: How is <broad> built? <broad> consists of one free base: <broad>. <broad> is a lexical word.
Question 3: What are the relatives of <broad>? Modern <broad> comes from Old English <brad> meaning “wide, not narrow.” Some related words include <abroad>, <broadly>, <broaden>, and <broadness>. <broad> is also related to <breadth>, which means “wide range or extent, width.”
Question 4: What sounds matter? <broad> spells [bɹɔd] or [bɹɑd]. The graphemes are <b.r.oa.d>.
But why does the <oa> spell [ɔ] or [ɑ] in <broad>. The graphemes <o> and <e> bear an etymological relationship as in <get> and <got> and <feet> and <foot>. The digraph <oa> also bears a relationship with <ea> as in <great> meaning “big” and <groat> meaning “a large coin.” The word <bred> is spelled with the grapheme <e> because of a relationship with the <ee> digraph in <breed>. In accordance with the homophone principle, English prefers to have different spellings for words that sound alike but have different meanings. The <e> in <bred> thus distinguishes the word from the <bread> in <breadth>. <board> is spelled with an <oa> to preserve the relationship with word <breadth>.
The digraph <oa> usually spells the phone [oʊ] as in <oat>, <loaf>, <soak>, <toad>, and <float>. In the word <broad>, however, the <oa> spells [ɔ] or [ɑ] depending on your English. Just as <o> and <oo> are related to <e> and <ee>, <oa> is related to <ea>. The <oa> in <broad> thus preserves the relationship with the <ea> in <breadth>. Understanding the spelling of <broad> is possible only by considering the history and relatives of the word in addition to the sounds.