A list that is not the main sentence message may or may not need to be introduced by a special list-showing expression
THE PROBLEM OF LIST-GIVING
Lists are common in academic and professional writing, where there is a regular need to give such listable information as aims, reasons, results, similarities, differences, examples, problems, solutions, conclusions and recommendations. Unfortunately, grammar errors are also common in list-giving by writers whose mother tongue is not English. Many of these comprise a chapter in my book Grammar Practice for Professional Writing.
Part of the challenge in list-giving is writing the words around it, and part is putting the list itself into the right grammatical form. The surrounding words vary according to whether the list is given in a single sentence or as bullet points or in multiple sentences, and in single-sentence listing according to whether or not the list is the main information being given. This post is about the words around a single-sentence list that is not being given as the main information.
The wording around a list that is the main information of a single sentence is the topic of the Guinlist post 55. Sentence Lists 2: Main-Message, while words accompanying bullet-point lists are in 74. Sentence Lists 3: Bullet Points. The problems of composing lists themselves, whether in sentences or as bullet-points, are the topic of the post 93. Good and Bad Lists. Advice on introducing and composing multi-sentence lists is offered in 122. Signpost Words in Multi-Sentence Lists. One other relevant post is 17. Colons versus Semi-Colons.
ILLUSTRATION OF INCIDENTAL LISTING
Lists that are given in a single sentence without being the main information there may be illustrated as follows (the lists underlined):
(a) It is useful to be able to understand Spanish and Portuguese.
(b) The two main languages of South America, Spanish and Portuguese, originated in Europe.
The list in (a) is incidental because the sentence is not primarily naming the list, but is indicating the usefulness of the listed things. In (b) too, the focus is not on the listed names of the main South American languages, but is on where they originated.
Despite this similarity between (a) and (b), there is a major difference. Only (b) contains what I call a “list name”: a noun-like expression next to the list that names the kind of thing being listed (the two main languages of South America). List names are general class names whose wider use is considered in the Guinlist post 162. The Language of Classification. In combination with an incidental list they make a special form of the grammatical structure known as “apposition” (see 77. Apposition (Pairing of Same-Meaning Nouns).
Combining an incidental list with a list name seems to be especially challenging, and is hence what the rest of this post is about.
WORDS THAT CAN INTRODUCE AN INCIDENTAL LIST
The main source of errors made by learners of English seeking to give an incidental list alongside a list name seems to be the use of special list-showing words between the list name and the list. There are two important things to know: which words are possible and when they should/can be used.
The words that are possible are of two main kinds: those suitable before an incomplete list, and those suitable before a complete one. A list is incomplete when it does not mention all of the members of the group represented by the list name (see 96. Hedging 2: Lists & Predictions). Take the group countries of the United Kingdom. A complete list would be Wales, Northern Ireland, England and Scotland; an incomplete list would be one lacking one or more of those. The following words are able to introduce an incomplete list:
Words that Introduce Incomplete Lists
such as …
for example …
for instance …
above all …
in particular …
The words in the first group here introduce (or, in the case of etc, follow) a list of examples. Lists of this kind are a randomly-chosen sample of the possibilities indicated by the list name, no different from the unmentioned ones (for more on examples, both single and in lists, see 1. Simple Example-Giving). The words in the second group, on the other hand, suggest that the mentioned possibilities are not randomly chosen, but are somehow more important than the unmentioned ones.
When the list is a complete one, the sentence is identifying rather than exemplifying or highlighting (see 117. Saying More Precisely What is Meant). The following expressions are usable:
Words that Introduce Complete Lists
in other words …
that is to say …
Note the absence from this list of which are. Some other languages allow an expression like it, but most English speakers simply do not use it. For more on abbreviations like i.e. and viz., see 130. Formal Abbreviations.
WHEN TO USE LIST-INTRODUCING WORDS
Incomplete lists always need to be introduced by one of the relevant expressions shown above. Sometimes a comma is needed before this expression, sometimes not: the rule is the one described for such as in the post 53. “As”, “Like” and “Such As”.
Complete lists, on the other hand, cannot always be introduced by one of the above expressions. The choice is free only if the list is surrounded by bracket-like commas (as defined in the post 50. Right and Wrong Comma Places):
(b) The two MAIN LANGUAGES OF SOUTH AMERICA, (namely) Spanish and Portuguese, originated in Europe.
If there are no commas, no list-introducing words can be present either:
(c) The two ANCIENT LANGUAGES Latin and Greek have left a strong legacy in Europe.
The simplest rule implied by these examples is that before a complete list it is always correct to have no list-introducing words at all. However, for readers who are interested in trying to use such words when they can, I offer some advice on when the commas that make them possible are needed.
Essentially you need to compare the list with the main words of the list name (i.e. the capitalised words in the sentences above, ignoring words like the and two before them). If the list and the main words of the list name stand for the same number of possibilities, then commas are needed (and you can use an expression like namely). This is the case in sentence (b). However, if the main words of the list name stand for more possibilities than are listed, then no commas are possible. This is the case in sentence (c), since other ancient languages exist than the two listed (e.g. Sanskrit).
Note that the lists in (b) and (c) are both “complete”, even though the lack of commas in (c) points to unmentioned ancient languages. This is because the and number words like two (at least one of which must always be present when a complete list is to follow) limit the list name each time to the number of items in the list. We ignore these words only to see whether or not commas are needed, and not to see how complete the list is. The logic behind these punctuation rules is actually similar to that described in the post 34. Relative Pronouns and Commas.
One final point to note is the position of the comma that words like namely always need: before them and not after. It is a common mistake to add punctuation after list-introducing words instead of before.