Check out "The Loom of Language: An Approach to the Mastery of Many Languages" by Frederick Bodmer. I'm reading it now and it's quite extraordinary. It seems

Check out "The Loom of Language: An Approach to the Mastery of Many Languages" by Frederick Bodmer. I'm reading it now and it's quite extraordinary. It seems like a particularly good fit for someone with your linguistic background, especially if you have an interest in learning further Germanic or Romance languages.