The main disadvantage of using a program to help you build a website if you have little or no understanding of markup languages is that the website you build is likely to be limited in functionality and unable to take advantage of the more advanced features available with markup languages. This can limit how effective the website is in achieving its purpose. Additionally, since you are likely unfamiliar with the language, creating sites can become more time consuming and errors can be more likely creating a longer learning curve as you work to build the website.