English developed from many languages. The old English developed from some Germanic dialets. Over time, English was influenced by latin. English is closely related to Frisian and the Celtic language.
To answer your question, yes, English was completely derived from other languages.
English was certainly adopted from other langugages. It is one of the Indo-European languages so it has been influenced heavily by other languages such as German and Latin. The North Sea Germanic languages of places such as Sweden and mainly Britian have contributed to the formation and the current standing of the English language today. The Celtic language also played a huge role in the formation of the English language.
Over the years as the English language evolved, it was able to get its influences from more and more places who chose to adopt English as one of its official languages. One can certainly say that English indeed was adopted from other influential languages. it was these languages that over time have brought it to the official and widely accepted status that it has these days. These languages can boast that they have given birth to the most widely spoken language in the world today.