Stylometric analysis
Stylometric analysis is the study of an author's writing style based on statistical analysis of their word usage, sentence structure, and other linguistic features. Some scholars have used stylometric analysis to argue that the works of Shakespeare were written by multiple authors, as there are significant variations in style and vocabulary throughout his plays and sonnets.
Lack of education and social status
Shakespeare was born in Stratford-upon-Avon, a small town in England, and there is no evidence that he attended university or received a formal education. This has led some to question how he could have acquired the extensive knowledge and vocabulary displayed in his plays, and has fueled speculation that he may have had help from more educated individuals.
The "dark lady" sonnets
Some of Shakespeare's sonnets, particularly those in the sequence known as the "dark lady" sonnets, are written from the perspective of a speaker who is infatuated with a dark-haired woman. This has led some to speculate that Shakespeare was writing about a real woman in his life, and that these sonnets may be autobiographical. However, there is no evidence to support this theory, and it is generally believed that the "dark lady" sonnets are simply works of fiction.
The complexity of the plays
Shakespeare's plays are often complex and sophisticated in terms of their language, themes, and characters. Some people have argued that it is unlikely that a man with Shakespeare's background would have been capable of writing such complex works, and have suggested that they may have been written by a more educated individual or group of individuals.
It is important to note that the vast majority of scholars believe that Shakespeare was the sole author of his plays and sonnets. The arguments presented above are based on interpretation and speculation, and there is no definitive evidence to support the claims that Shakespeare's works were written by someone else.