Short answer: I’m not aware of any peer‑reviewed study that documents a nonhuman group systematically changing their communication specifically for a chronically deaf conspecific (e.g., consistently calling louder/closer to that individual or routinely switching to tactile signals only with that individual). Such cases are probably rare for two practical reasons: (1) confirmed deafness is hard to diagnose in free‑ranging animals, and (2) in taxa where hearing is crucial for survival, fully deaf individuals likely have low survival or reproductive success, giving little opportunity for group‑level accommodation to be observed.

That said, several well‑studied phenomena show that many social species already adjust signals to the perceptual state of receivers on a moment‑to‑moment basis (receiver- and audience-directed communication), and these adjustments would plausibly extend to a hearing‑impaired group member if one were present:

• Modality switching and persistence in great apes: Chimpanzees, bonobos, and gorillas choose signal modality based on a partner’s attentional state and escalate/persist if initial attempts fail—e.g., they use more audible gestures when a partner is not looking and switch to tactile/visual signals (touching, slapping, objects) if needed. This shows flexible, recipient‑directed signaling that would likely be used with a deaf partner, although chronic deafness per se has not been studied. • Hobaiter & Byrne 2011 Animal Cognition; Genty & Byrne 2010 Animal Cognition
  • Hostetter et al. 2001, 2007 (chimpanzees modulate vocal vs. gestural signals by recipient attention)

• Adjusting signal amplitude in adverse listening conditions (Lombard effect): Many birds and mammals (including primates, bats, cetaceans) automatically increase call amplitude when background noise rises, functionally akin to “speaking up” for a harder‑to‑hear receiver. This is well documented but has been tested with environmental noise rather than partner deafness. • Brumm & Zollinger 2011 Trends in Ecology & Evolution; Zollinger & Brumm 2011 Current Biology

• Audience effects in alarm calling: Some species call more, or in different ways, when receivers are naïve or at higher risk. Wild chimpanzees, for example, produce more warning calls when group members are unaware of danger; cooperative breeders (e.g., meerkats, pied babblers) vary alarm and sentinel calls by who is present and how risky the situation is. This shows sensitivity to who “needs” information and could translate into extra support for individuals likely to miss acoustic cues. • Crockford et al. 2012 Current Biology (chimpanzees inform ignorant group members)
  • Manser 2001 PNAS (meerkat alarm structure); Hollén et al. 2008 Proc. R. Soc. B (pied babblers adjust sentinel calls)

• Multimodal redundancy: Elephants, many primates, and cetaceans routinely combine acoustic with seismic, visual, or tactile signals and increase redundancy when transmission is uncertain (distance, wind, noise). While not studied for deaf receivers, these systems provide built‑in alternatives. • O’Connell‑Rodwell 2007 J. Comp. Physiol. A (elephant seismic communication)
  • Janik & Sayigh 2013 Animal Behaviour (dolphin signature whistles and addressing)

• Adjustments to receivers with limited perceptual/cognitive capacities (infants): Several primates and birds alter call structure or interaction timing for infants (e.g., “infant‑directed” vocalizations; contingent parental feedback), indicating sensitivity to receiver-specific processing limits. • Takahashi et al. 2015 Science (parental feedback tunes marmoset vocal development)
  • Reviews on infant‑directed vocalizations in nonhuman primates (e.g., Zimmermann 2014)

What seems to be missing are confirmed cases where (a) an individual is diagnosed as partially/fully deaf and (b) conspecifics are shown to systematically adapt communication specifically for that individual over time. Captive populations (e.g., great apes, dolphins, social canids) and domestic animals with known congenital deafness (e.g., Dalmatians, white cats) would be the most feasible systems to test this directly, but formal studies are scarce.

In summary: No direct, published examples of group‑level accommodation to a deaf individual in nonhuman species appear to exist. However, many social animals already tailor signal modality, amplitude, redundancy, and calling behavior to receiver attention, distance, noise, and need—behaviors that would plausibly serve to include a hearing‑impaired group member if such an individual were present and recognized.