zhèngfǔ yǒu yí gè xīn jìhuà.

This is because of tone change (tone sandhi).

一 is normally pronounced yī when said by itself or when counting: 一，二，三.

But in connected speech, its tone often changes:

• before a 4th-tone syllable, 一 becomes yí
• before a 1st, 2nd, or 3rd-tone syllable, it usually becomes yì

Here, 个 is pronounced gè and has a 4th tone, so 一 个 is pronounced yí gè.

So:

• written form: 一个
• actual pronunciation here: yí gè

个 is a measure word (also called a classifier).

In Chinese, when you say a / one + noun, you usually need:

• a number
• a measure word
• the noun

So 一个计划 literally follows this pattern:

• 一 = one
• 个 = measure word
• 计划 = plan

English does not usually need this extra word, but Chinese does.

个 is the most common general-purpose measure word, and it is often used with many nouns, especially in beginner Chinese.

This follows a very common Chinese pattern:

Topic/subject + 有 + quantity + description + noun

So here:

• 政府 = government
• 有 = has / there is
• 一个 = one / a
• 新 = new
• 计划 = plan

So the structure is basically:

The government + has + a + new + plan

Chinese word order is often quite similar to English in simple sentences like this.

In Chinese, adjectives usually come before the noun they describe, just like in English.

So:

• 新计划 = new plan
• 大城市 = big city
• 好办法 = good method

That makes 一个新计划 literally one new plan, which is very close to English word order.

Chinese does not have articles like a, an, and the in the same way English does.

So 政府 can mean:

• government
• the government

Which one is meant depends on context.

In this sentence, English would naturally say The government has a new plan, but Chinese does not need a separate word for the.

Not always.

有 often means:

• to have
• there is / there are

In this sentence, 政府有一个新计划 means The government has a new plan.

But in another sentence, it could mean existence:

• 这里有一个商店。 = There is a shop here.

So 有 can express either possession or existence, depending on the sentence.

Yes. 计划 can be either a noun or a verb.

In this sentence, it is a noun:

• 一个新计划 = a new plan

But it can also be a verb meaning to plan:

• 我们计划明天出发。 = We plan to leave tomorrow.

This is common in Chinese: the same word can sometimes function as different parts of speech depending on context.

Because 政府 is the subject here, not part of a number + noun phrase.

Measure words are usually needed when a noun is counted or specified with words like:

• 一
• 两
• 这
• 那

For example:

• 一个计划 = one plan
• 这个计划 = this plan

But in 政府有一个新计划, 政府 is just the subject, so no measure word is needed there.

You would usually put 没 or 没有 before 有.

So:

• 政府没有一个新计划。

But in natural Chinese, that sentence can sound a bit unusual depending on what exactly you mean.

More natural possibilities are often:

• 政府没有新计划。 = The government doesn’t have a new plan.
• 政府没有这个计划。 = The government does not have this plan.

A useful rule:

• 有 is usually negated with 没有
• not with 不有

So learners should remember:

• 有 → negative form: 没有

Yes, you can.

There is a small difference in feel:

• 政府有一个新计划。 = The government has a new plan.
  This points to one specific new plan.

• 政府有新计划。 = The government has new plans / has a new plan / has new planning, depending on context.
  This is a bit less specific and can sound more general.

So 一个 makes the idea more clearly countable and singular.

Grammatically, 政府 does not change form for singular or plural the way English nouns sometimes do.

Here, it normally means the government as a single institution.

Chinese nouns generally do not change form for plural:

• one government: 政府
• governments: often still 政府, if the context makes it clear

If needed, Chinese can add other words to show plurality, but often context is enough.

A natural pronunciation would be:

Zhèngfǔ yǒu yí gè xīn jìhuà.

A few helpful points:

• 政府: zhèng is 4th tone, fǔ is 3rd tone
• 有: 3rd tone
• 一 becomes yí here
• 个 is usually taught as gè (4th tone)
• 计划: jì is 4th tone, huà is 4th tone

In normal speech, the sentence flows smoothly, and learners should especially pay attention to:

• the changed tone in 一
• the cluster of 4th tones in 新计划? Actually 新 is 1st tone, then 计划 is 4th + 4th, so it ends with a firm falling rhythm

Yes, in English that is also a very natural translation.

Because Chinese often does not mark possession and existence as differently as English does, 政府有一个新计划 can be understood as:

• The government has a new plan
• There is a new government plan

But the most direct grammatical reading is The government has a new plan. The exact English wording depends on what sounds most natural in context.