Original: The sarati , described in Parma Eldalamberon 13 , a script developed by J. R. R. Tolkien in the late 1910s , anticipates many features of the tengwar , especially the vowel representation by diacritics ( which is found in many tengwar varieties ) , different tengwar shapes and a few correspondences between sound features and letter shape features ( though inconsistent ) .
Simplified: In the late 1910s , J. R. R. Tolkien developed the script Sarati , which was already a bit similar to tengwar . The tengwar were probably developed in the late 1920s or in the early 1930s .