To describe charts in audio lessons, explain the question the chart answers before walking through selected values. A listener needs to know the subject, the comparison, and the units. Reading every label in visual order often obscures the relationship the lesson is trying to teach. Keep detailed data available separately for inspection.
Write the chart's message in one sentence
Start with a plain statement such as “weekly support requests fell after the new help page launched.” Then check whether the chart actually supports that statement. A before-and-after pattern does not by itself prove why the change happened, so avoid turning a visual association into a causal claim.
Identify what is measured, over what interval, and in what units. “Requests fell from eighty to fifty per week” is clearer than “the blue line drops.” If several series appear, name them by meaning instead of color alone.
Decide which comparison the lesson needs: highest versus lowest, beginning versus end, a change in direction, or a difference between groups. Use that choice to determine the narration order. The order does not have to follow the chart from left to right if another route makes the explanation easier to follow.
Keep the underlying table with the lesson for readers who need exact values.
Build a spoken path through the evidence
Use an orientation sentence, a main comparison, and one supporting detail. For an original example: “The chart tracks weekly returns across three months. Returns decline from forty in April to twenty-five in June. May sits between them at thirty-two, so the decrease happens across both intervals.”
State an exception when it changes the interpretation. If the final week spikes, do not smooth it away to preserve a simpler story. Similarly, explain a changed scale or missing interval if the lesson relies on reading that feature correctly.
W3C's visual-information guidance includes charts among visuals whose essential information may need description. Your script should convey the lesson's actual evidence, not offer a generic sentence announcing that a chart exists.
For dense data displays, use the table narration workflow to separate a spoken overview from a complete text reference.
Coordinate speech with the visual reveal
If the chart appears in a slide deck, keep its title visible while the narration establishes the subject. Highlight the relevant series or point during the matching sentence, then leave time to inspect the comparison. Create these visual actions in the presentation or video editor.
Avoid timing the explanation to a rapid animation that forces viewers to remember values that disappear. Where possible, leave previous values visible so the relationship remains inspectable. If an animation is necessary to demonstrate change, describe the important state transitions in the script.
Use stable references in assembly notes: “highlight June returns” is safer than “highlight the last bar” when a designer may add another month. The narrated slide deck template gives those notes their own column.
Preview the generated audio against the final graphic. Small layout edits can change what “above,” “below,” or “the second group” refers to, even when the numerical data stay the same.
Check the description without the image
Ask a reviewer to explain the chart's main relationship after hearing the narration without seeing it. Then show the chart and ask whether anything essential was missing or overstated. These are different checks: understandable speech can still describe the wrong values.
Verify each spoken number against the source data. Write units in the speech script when symbols might be read ambiguously. Keep a separate published version with conventional notation and a clear heading for the data table.
Add the description to the lesson's text alternative, preserving any important qualifications. Regenerate only after the data owner approves the factual interpretation.
Try the main comparison in the voice studio. Listen for whether the units, direction of change, and exception can all be understood in one pass, then adjust sentence structure before extending the description.
