Each speaker or author is free to speak or write on topics of their own choosing, to audiences of their own choosing, in their own choice of language and their own choice of words, without hindrance from the government. Software has been written for years without general examination of its free speech aspects. Movies started off being treated by the courts as mere flickering light-machines run by businesses, that they were free to regulate. It took almost 35 years to overturn that model, seeing them as a medium of expression for which regulation was forbidden. A straightforward look at software will show clearly how it deserves First Amendment protection.
Software is written by humans, like fully protected books or magazine articles.
Programs are filled with ordinary human language, in the form of comments and names. The essence of free speech is the publication of communicative words. Software was originally published in such forms only in tiny quantities, such as in the Algorithms section of the Communications of the ACM magazine, since it was painful to manually punch these programs into cards for use with a computer. Still, they were published for readers to examine and understand. The next major stage was publication on computer-readable media, such as floppy disks or tapes.