Short answers, pulled from the story.
Estimates of native Uzbek speakers range from 30 million to 40 million, depending on the source. The Nationalencyklopedin estimates 38 million, the CIA World Factbook estimates 30 million, and Ethnologue puts the figure at 33 million across all recognized dialects.
Uzbek has been written in four different scripts since 1000 AD: Arabic, Latin (Yanalif), Cyrillic, and Latin again since 1992. Despite the official status of the Latin script in Uzbekistan, Cyrillic remains widely used in advertisements, signs, and publications. In Xinjiang, Afghanistan, and Pakistan, Uzbek communities still use the Arabic script.
Chagatai was a Karluk Turkic literary language used across Central Asia from the medieval period through the early 20th century. Uzbek is considered its direct descendant. In 1924, Soviet officials renamed Chagatai "Old Uzbek" as part of the establishment of the Soviet Republic of Uzbekistan.
Vowel harmony is almost completely absent from modern Standard Uzbek due to centuries of intensive contact with Persian. Most other Turkic languages retain vowel harmony, but Uzbek's long history of Persian influence has eroded this feature from the standard variety, though some dialects still preserve it.
Afghanistan is estimated to have 4.5 million Uzbek speakers, Pakistan around 1.6 million, Tajikistan around 1.5 million, Kyrgyzstan about 1 million, Kazakhstan and Turkmenistan each around 600,000, and Russia around 300,000. Russian government statistics in 2021 counted approximately 5 million ethnic Uzbeks in Russia overall.
Persian has most heavily influenced Uzbek vocabulary, phraseology, and pronunciation. Arabic loanwords entered through Islam. Russian contributed technical, modern, and sociopolitical terms during the era of the Russian Empire and Soviet Union. Uzbek also contains roughly 60 Mongolian loanwords, concentrated in animal names, household items, and military terms.