From January to April 2006, Cameron worked on the script and developed a culture for the film's aliens, the Na'vi. Their language was created by Dr. Paul Frommer, a linguist at USC. The Na'vi language has a lexicon of about 1000 words, with some 30 added by Cameron. The tongue's phonemes include ejective consonants (such as the "kx" in "skxawng") that are found in the Amharic language of Ethiopia, and the initial "ng" that Cameron may have taken from New Zealand Māori. Actress Sigourney Weaver and the film's set designers met with Jodie S. Holt, professor of plant physiology at University of California, Riverside, to learn about the methods used by botanists to study and sample plants, and to discuss ways to explain the communication between Pandora's organisms depicted in the film.From 2005 to 2007, Cameron worked with a handful of designers, including famed fantasy illustrator Wayne Barlowe and renowned concept artist Jordu Schell, to shape the design of the Na'vi with paintings and physical sculptures when Cameron felt that 3-D brush renderings were not capturing his vision, often working together in the kitchen of Cameron's Malibu home. In July 2006, Cameron announced that he would film Avatar for a mid-2008 release and planned to begin principal photography with an established cast by February 2007. The following August, the visual effects studio Weta Digital signed on to help Cameron produce Avatar. Stan Winston, who had collaborated with Cameron in the past, joined Avatar to help with the film's designs. Production design for the film took several years. The film had two different production designers, and two separate art departments, one of which focused on the flora and fauna of Pandora, and another that created human machines and human factors. In September 2006, Cameron was announced to be using his own Reality Camera System to film in 3-D. The system would use two high-definition cameras in a single camera body to create depth perception.While these preparations were underway, Fox kept wavering in its commitment to Avatar because of its painful experience with cost overruns and delays on Cameron's previous picture, Titanic, even though Cameron rewrote the script to combine several characters together and offered to cut his fee in case the film flopped. Cameron installed a traffic light with the amber signal lit outside of co-producer Jon Landau's office to represent the film's uncertain future. In mid-2006, Fox told Cameron "in no uncertain terms that they were passing on this film," so he began shopping it around to other studios, and approached Walt Disney Studios, showing his proof-of-concept to then-chairman Dick Cook. However, when Disney attempted to take over, Fox exercised its right of first refusal. In October 2006, Fox finally agreed to commit to making Avatar after Ingenious Media agreed to back the film, which reduced Fox's financial exposure to less than half of the film's official $237 million budget. After Fox accepted Avatar, one skeptical Fox executive shook his head and told Cameron and Landau, "I don't know if we're crazier for letting you do this, or if you're crazier for thinking you can do this ..."

Question: Who assisted Cameron in making avatar?
Answer: Weta Digital