Most Welsh speakers experience primary care services through the medium of English, an inquiry by Welsh Language Commissioner Meri Huws has concluded.
The investigation found that only 28% of Welsh speakers had used the language with their GPs, dentists and opticians.
Ms Huws said she hoped her report was the "beginning of the end" for patients being unable to have healthcare "appropriate to their needs".
Welcoming the report, ministers said they would respond within six months.
The inquiry, based on the experiences of more than a thousand Welsh speakers, found that 90% of them agreed that they should have the right to use the language when dealing with NHS wherever they live in Wales.
Other findings included that:
- Welsh speakers were most likely to experience care in Welsh with a practice nurse but least likely to with out of hours services, dentists and opticians
- 55% of the contact with a practice nurse in Welsh was in the Betsi Cadwaladr University Health Board area, but it falls to 6% in south and mid-Wales
- 83% agreed agreed that if health professionals were available Welsh language appointments should be offered to Welsh speakers every time
Welsh speakers who gave evidence to the inquiry reported feeling awkward and struggling to explain their feelings to an English speaking doctor.
The report makes 33 recommendations to the Welsh government, calling on ministers to provide a "clear policy lead" to primary care providers, together with an "action plan" and "timetable for change".
Launching the document in Cardiff Bay, Ms Huws said: "I have been very concerned to hear of some worrying experiences that Welsh speakers and their families have had to face in not being able to access healthcare appropriate to their needs.
"I truly hope that this report is the beginning of the end to such experiences."
However, she said she was "encouraged" by the "constructive approach" of many organisations and individuals in the NHS.
"The report highlights that the Welsh language is an integral part of the quality of healthcare and that a Welsh language or bilingual service is vital for the welfare of Welsh speaking patients.
"I hope this report will be the start of a discussion leading to action on the recommendations in order to improve the quality of primary care in Wales," Ms Huws added.
In a statement, the Welsh government said: "We welcome the publication of the Welsh language commissioner's report.
"We will provide a full response to all the recommendations within the next six months, as requested.
"We are moving forward with actions set out in our health, social service and social care Welsh language strategy, More Than Just Words, which was launched in November 2012, with a three-year action plan.
"The commissioner's report will augment this work."