Users type keywords into the search engine as they occur to them, without stopping to think if they are standardized marketing terms or if they are better or worse written, often ignoring even the correct grammar. In the context of keyword research, the smartest thing to do would therefore be to consider different ways of writing a certain search term . This affects, in particular, the use of synonyms, which, although they are recognized by search engines as such, are considered as independent words.
The word combinations also give users a large margin when defining their search. In the context of a keyword search, web managers constantly stumble upon terms that can be used together or separately, leading to different search results. Here it must be borne in mind that the hyphens are interpreted as spaces : if a user is looking for a shoulder bag or shoulder bag, it is indifferent. In this example, the search engine returns, in both cases, 2900 monthly searches.
The importance of integrating different versions of a combination of words in the list of keywords does not support a single answer as it depends on each particular case, although, in general, the correct way to write these words should be included.
Whether a word is written in lowercase or uppercase or if it is inflected (verbal person, number, tense) is no longer so relevant. The keyword shoe does indeed yield different results than it does shoes, but in general the different grammatical variations of a keyword can be easily covered by the content of the web page. Defining separate landing pages for the different inflected forms of the keywords doesn't make much sense.
In current SEO , typing errors in key terms have also lost relevance due to the search engine's self-correcting function. Google, for example, recognizes misspelled words and automatically returns results that correspond to the correct form of the word. And that's not to mention that accepting a misspelled word as a keyword means having to integrate it, also misspelled, into the texts on the page, something that crawlers value negatively and that gives readers a very bad impression. If, despite everything, it is convenient that misspelled words, but with a remarkable volume of searches, have to be considered as relevant keywords, then it is better to use them in advertising in search engines or SEA.