Solid line = floor (spellings that unambiguously belong to the group). Shaded band up to the dashed edge = ceiling (the most it could reach if every ambiguous spelling counted here).
Judah has been climbing in recent years. All-time it's been given to 36,431 U.S. babies, the 371st most common name by sound today, peaking at 2,178 in 2021, with 2,091 in 2025.
Judah has no common alternate spellings by sound.
Source: U.S. Social Security Administration, “National data” baby-names files (1880–2025).