What is the ”everyday” of the everyday language Wittgenstein talks about in the Philosophical Investigations? Actually, there are several contrasts between the everyday and the non-everyday that seem to be of relevance in connection with Wittgenstein’s thought.
In most cases in the Philosophical Investigations where the English has ”everyday” it’s a translation of “alltäglich” (§ 106 “alltägliches Denken”, § 116 “alltägliche Verwendung”, § 134 “alltägliche Sprache”, § 412 “alltäglicher Sinn”). In § 81 Wittgenstein uses the word “Umgangssprache” [literally “the language of social intercourse”]. The contrast in most of these cases is with a metaphysical use (§ 116) or with an ideal language (e.g. §§ 81, 106, 134); as we might put it, with a language imagined by philosophers, a language in which things are expressed, as it were, in a mode true to their real essence; this could also be something like Frege’s concept script which, although it may not be intended for actual use, is supposed to express thoughts in a logically transparent way. This idea exerted a powerful attraction on philosophers of the day, but Wittgenstein at this stage considered its attraction to be insidious: the idea that such an imagined language might somehow deepen our understanding of our concepts was illusory. To get clear about them we should attend to their actual uses.
§ 18 hints at a different contrast:
Our language can be regarded as an ancient city: a maze of little streets and squares, of old and new houses, of houses with extensions from various periods, and all this surrounded by a multitude of new suburbs with straight and regular streets and uniform houses.
Here the contrast is between different areas of our actual language. The suburbs, it would appear, are mainly symbolic of the technical terminologies used in science and in various professions, words like “ionized”, or “erythrocyte”, or “conditioned reflex”, or “Alzheimer’s disease”, or “eminent domain”. These are well-regulated terminologies, often created by means of stipulative definitions, and hence their use is mostly easy to survey, in distinction to that of the central parts of the city with its mixture of old and new buildings, and a street pattern that has developed more organically. It is because the organic, “vernacular” parts of language (we might call it the language of everyman, and every woman) are difficult to survey that they tend to give rise to philosophical problems. The suburbs hold less of philosophical interest. They are a kind of artifical language. (Though sometimes seemingly clean and straightforward technical terms carry a subconscious burden inherited from the areas of language out of which they have been created. Or they may take on a life of their own, perhaps returning to the contexts of everyday conversation.)
Many, though not all, of the words belonging to what might be called the ageless core of our language are philosophically problematic because they have a variety of different but related uses, and thus tend to recur in a large variety of contexts: I am thinking of words such as “see”, “know”, “think”, “will”, “feel”, “mean”, “time”, “because”, “just”. (In some passage that I have been unable to retrieve, Strawson, I believe, refers to this vocabulary as words without a history. In some sense, we might say, they have always been there. Indeed, what would it be to imagine language without them?)
Wittgenstein makes a related point, in Remarks on the Philosophy of Psychology, Volume II:
§ 216 ... our concept “thinking” is widely ramified. Like a ramified traffic network which connects many out-of-the-way places with each other.
§ 218 Couldn’t the same be said of “believing”, “doing”, “being glad”?
Between the “ageless” and the artificial lie words with a history, words such as “religion”, or “citizen”, or “intelligence”, or “literature”. They too give rise to philosophical bewilderment, but maybe not as deep or intractable as the other kind. (This trichotomy is not intended to be exhaustive, simply to point to some characteristic differences between types of words.)
A third contrast is that between thinking about a word or sentence in isolation and thinking about its role in human interaction; holiday vs. workday. This of course is the theme of two oft-quoted remarks in the Philosophical Investigations:
§ 38: Naming seems to be a strange connection of a word with an object. – And such a strange connection really obtains, particularly when a philosopher tries to fathom the relation between name and what is named by staring at an object in front of him and repeating a name or even the word “this” innumerable times. For philosophical problems arise when language goes on holiday. And then we may indeed imagine naming to be some remarkable mental act , as it were the baptism of an object.
§ 132: ... a reform for particular practical purposes, an improvement in our terminology designed to prevent misunderstandings in practice, may well be possible. But these are not the cases we are dealing with. The confusions which occupy us arise when language is, as it were, idling, not when it is doing work.
Here the idea is that our bewilderment is dissolved when we attend to the actual functioning of our expressions. Not because doing so provides answers to our questions, but because it reminds us that in the context of actual conversation, the problems that beset us do not arise. The need to attend to actual functioning, of course, does not simply concern the language of social intercourse, but the languages of the sciences, law, theology, etc as well. The everyday of the language, not just the language of everyday.