IELTS Process Diagram Vocabulary — Sequencing, Passive Voice, Transitions

Why process vocabulary is different

In a line graph or bar chart, your vocabulary is about movement — rises, falls, fluctuations. In a process diagram, your vocabulary is about sequence and transformation — what happens first, what happens next, and how one thing becomes another.

The examiner is checking two things: can you sequence stages without being robotic, and can you use passive voice consistently? Below are the seven categories of vocabulary you will need for any process diagram on the exam.

The vocabulary categories

Beginning a process

at the initial stagethe process begins withfirstinitiallythe raw materials are

"At the initial stage, limestone and clay are fed into a crusher."

Sequencing — moving between stages

subsequentlyfollowing thisat the next stageonce X has been completedafterthenthe next step involves

"Following this, the powder is mixed and passed through a rotating heater."

Simultaneous actions

at the same timemeanwhilesimultaneouslywhile X is being doneduring this stage

"While the powder is being heated, the grinder is prepared for the next stage."

Transformation — one thing becomes another

is converted intois transformed intobecomesis turned intois processed into

"The heated mixture is then processed into cement in the grinder."

Ending a process

at the final stagethe end product isthe process concludes withfinallythe finished X is then

"At the final stage, the finished cement is packaged in bags for commercial distribution."

Equipment and agents

is fed into a crusherpasses through a heateris placed in a mixeris transported viaenters a

"The powder is then passed through a rotating heater at approximately 1400°C."

Cyclical processes

the cycle begins againthis stage feeds back intothe process repeatsis recycled back to

"Once the water has evaporated, it condenses and the cycle begins again from the first stage."

Common vocabulary mistakes

These are real mistakes from student process diagram reports. In each case, the problem is not grammar — it is using the wrong voice, the wrong connectors, or adding information that is not in the diagram.

Active voice

"Workers crush the limestone and clay into a fine powder."

Passive voice

"The limestone and clay are crushed into a fine powder."

The diagram does not show any workers. You are describing a process, not the people who perform it. Passive voice removes the agent and focuses on what happens — which is exactly what the examiner wants. Using active voice with an invented subject ("workers", "they", "people") is adding information that does not exist in the diagram.

Robotic sequencing

"First, the limestone is crushed. Second, the powder is mixed. Third, it is heated. Fourth, it is ground."

Varied sequencing

"Initially, the limestone is crushed. Following this, the powder is mixed. Once completed, the mixture is heated. At the final stage, it is ground."

"First, Second, Third, Fourth" is a numbered list, not a report. The examiner is testing whether you can link stages naturally. Varied connectors signal genuine control over cohesion and earn higher marks in Coherence and Cohesion.

Adding opinions

"This is a very efficient process that produces high-quality cement."

Neutral description

"The process involves four stages and results in the production of cement."

Task 1 never asks for your opinion. You are describing what you see, not evaluating it. Words like "efficient", "effective", "high-quality", or "well-designed" have no place in a process diagram report. The examiner treats them as off-topic content.

Tense — present simple passive for almost everything

Process diagrams are simpler than other Task 1 types when it comes to tense. Unless the process is explicitly historical (for example, "how pottery was made in ancient Greece"), you should use present simple passive for the entire report.

Present simple passive

For general / current processes (most process diagrams)

"The limestone is crushed into a fine powder."

Past simple passive

For historical or completed processes

"The clay was shaped by hand and dried in the sun."

This is much simpler than line graphs, where you might need to shift between past simple, present perfect, and future forms. For process diagrams, present simple passive is correct in the vast majority of cases. Stick with it unless the diagram clearly shows a historical process.

Your teacher's note

Process diagrams are the one Task 1 type where vocabulary is more predictable than it seems. You only need about 20 phrases to handle any process — five for sequencing, five for transformation, and the rest for equipment and endings. Learn them, practise them, and you will never be stuck on a process diagram again. The passive voice pattern is the same every time: subject + is/are + past participle.