Communication is fundamental to how we work, learn, and participate in society. Digital communication tools open opportunities for expanded inclusion, but they can also create barriers that exclude people with disabilities if not designed with care. Design choices—from documents that screen readers cannot navigate to video meetings without captions—determine who can access information and contribute to conversations. This lecture examines how to design communication systems that work for everyone.
We'll explore two major categories of digital communication: asynchronous tools like documents and synchronous tools like video conferencing platforms. For documents, we'll examine how structure, reading order, and alternative text affect accessibility. For meetings and events, we'll look at real-time communication challenges—captioning technologies, sign language interpretation, and the coordination required for accessible hybrid events. Throughout, we'll see how accessibility barriers don't just inconvenience users—they can make participation completely impossible.
Documents are persistent communication artifacts, often in a format like PDF and Microsoft Word. Like apps and websites, their accessibility determines whether all users can independently access and understand the information they contain.
Well-structured documents help users understand how content is organized, locate information quickly, and build mental models of how ideas relate. This matters especially for screen reader users—a clear mental model of document structure significantly improves their ability to access information. Use tables of contents, headings, lists, and summaries effectively.
For screen reader users, headings function as navigational waypoints; they can view a heading list, jump between sections, or navigate by level. This only works with semantic heading styles, not visual formatting like bold or large text. When authors create "fake" headings (bold text not semantically marked as a heading), screen reader users must read entire documents linearly while sighted users scan quickly. Heading hierarchy matters: skipped levels (H2 to H4) break mental models and force users to guess at the document's structure. Consistent heading levels help users with cognitive disabilities understand how ideas relate and predict how content is organized.
Properly formatted lists provide semantic meaning that enhances comprehension. Screen readers announce "list of 5 items" and track position ("item 3 of 5"), helping users prepare for and navigate information. Manually created "lists" using dashes or asterisks—like fake headings—provide no structure. Users hear disconnected lines of text without understanding they form a group. The distinction between ordered and unordered lists also carries meaning. Numbered lists imply sequence or priority; bulleted lists suggest equivalent items. This semantic information disappears when formatting is purely visual.
Summaries help users with memory difficulties review and reinforce key points. They allow users with attention challenges to assess whether to read the full document. Time-pressed users can quickly evaluate relevance. Tables of contents extend this principle by providing navigable overviews. For long documents, they make the difference between usable and unusable content for users with cognitive disabilities who cannot hold entire document structures in working memory.
Visual layout often differs from the logical reading order that screen readers follow. When reading order is incorrect, comprehension breaks down. Sidebars might interrupt the main text, or columns might read across rather than down, creating nonsensical jumbles. Users experience confusion and cognitive overload as they mentally reconstruct logical flow from fragments. Multi-column layouts, floating text boxes, and complex page designs all require careful attention to reading order. What appears visually organized may become chaos when linearized for assistive technologies.
When screen reader users encounter images without alt text, they hear "image" or meaningless filenames. Effective alt text delivers information beyond what appears in the caption. Complex images require layered approaches: brief alt text for overview, detailed descriptions in surrounding text, and data tables for precise values. This serves users with different needs—some scan quickly, others analyze in depth. Good alt text throughout a document creates cognitive flow. Users maintain comprehension momentum rather than repeatedly stopping to puzzle over missing information. They participate as equals in visual discussions and trust that their needs are considered.
Meetings and events like conferences require synchronous communication, which presents unique accessibility challenges. Participants must process information in real time across multiple sensory channels. Whether you're using existing software systems or creating new ones for synchronous communication, understanding how individuals with different abilities experience these environments is essential.