“All” is both singular and plural. We only use it in the singular or plural forms when there is a specific word after it that follows a specific form. For example, “that is all” works beca… See more

“All” is singular whenever we use it with a singular noun. We know this because it will use words like “that” or “it.” It’s simple to work out whether we need the singular form because w… See more

“All” is plural in some cases, though. We use it whenever we’re dealing with plural nouns or groups of things. Any time where words like “these” or “those” are used, “all” is plural. Si… See more

According to Google Ngram Viewer, “all is” is more popular, but only just. Both forms are very common, which shows that it’s entirely dependent on the context as to which form … See more